Exit the Hogwarts castle via the great door to the south.
Ron will lead you to the garden path where you must pick your way through to get to Hagrid's hut. The path is on the left of the Castle Grounds. When you enter the gardens, you will see a scroll which warns of poisonous mushroom patches, an example of which is beside the scroll. They hurt you when you come in contact with them so watch it. Anyway, here's a step by step guide for getting to Hagrid's hut.
1. Go left and knock out the golden gnome. Then fire four Flipendo blasts at the thorny bush blocking your way into another area. Avoid the spines it ejects when you hit it with the Flipendo jinx. Avoid the mushroom patches, mud which sinks in and lets you fall through, and search the bush at the end of the room for a bag of Jellybeans. Knock out the golden gnome wandering around.
2. Exit that place, and go left and forward, past two big logs and across a wooden "carpet". You should see a thorny bush and a light brown log. Fire four Flipendo blasts to wipe out the thorny bush, go forwards and right, knock out the golden gnome, and cast Flipendo across the small pond to push another light brown log at the end.
3. Double back and use Flipendo to push the first light brown log horizontally several times, until you can pick your way forwards and left to another area. Knock out the gnome and go south, avoiding the mushrooms, to yet another area.
4. Go left and follow the path until you see a closed door, thorny bush and a gnome. Knock out the gnome, then neutralise the thorny bush. Go through the opened path to Hagrid's hut.
In Hagrid's hut, you tell him that you need to find Dittany, and he leads you to another area. Save at the Save Point in his hut and follow him outside into his garden.
Find the Dittany!
To help you find it a little easier, I'll tell you what Dittany looks like, so you can tell whether that's a poisonous mushroom patch or your goal. It's a small, brown, mushroom-like thing. Now, a step by step guide to get the Dittany. Oh, why did Hagrid have to grow Dittany all the way at the back?!
1. Go to the left. You will see a small patch of land isolated by a pit. The patch of land has a pressure plate and a white plant on it. Cast Flipendo on it (the direction doesn't matter, so long as it's not diagonal) twice to make it roll onto the pressure plate and stay there. This will enable a small moving bridge.
2. Double back a little and walk onto the moving bridge. Don't fall now! When you get to the other side, you'll need to knock out the gnome in the way (bush contains nothing) and go left and down to find another white plant. Fire Flipendo at it from the right and push it onto a pressure plate, enabling a moving bridge. But there are three pressure plates! You'll need to locate two more plants.
3. Go down and you'll see a white plant. Fire Flipendo at it from the left and set it rolling. Take down the thorny bush, and roll the white plant downwards, such that it stops beside a chasm. Then double back a little, and fire a Flipendo blast across the chasm from the left, pushing the plant against a log. Go behind the plant and push it downwards again.
4. Now you'll see two thorny bushes. Neutralise the one on the right, then go into the area and fire Flipendo from the right across the chasm, pushing the plant.
5. Now use Flipendo to push the plant forward and left past a thorny push, until you see a Flipendo block is barring the way. Shift the block over the chasm by firing Flipendo at it from the left, and doubling back in front of the plant and pushing it the rest of the way, until it ends on a second pressure plate.
6. Double back and go to the left past a thorny push, knock out the gnome there and push the pressure plate. This will set off another platform moving, but not the last one, which you need to hold down the third pressure plate with a third plant. Walk onto the platform and get carried to the other side.
7. Knock out the gnome over there, go downwards and search the left bush for a Chocolate Frog. Now go downwards again, and AUGH! Three gnomes rush up to meet you, so take care of them and grab the jellybean. Go downwards more, until you reach a dead end with a white plant on the other side of a chasm. Fire Flipendo at it from the left and push it away.
8. Now double back and head right this time. Search the bush for a bad of Jellybeans, and neutralise the throny bush nearby. Now go downward, trash both gnomes wandering around, neutralise both thorny bushes, take another bag of jellybeans, and shift the Flipendo block over a chasm. Now double back a little and push the plant across the cleared path.
9. Follow where the plant has rolled, go in front of it, and push it forwards. Then you must carefully walk between the plant and chasm, and fire a Flipendo spell to the right of the plant, pushing it left.
10. Now work your way forward and left, past the shifted Flipendo block, like you did for the second plant, until the last plant is pushed onto the last pressure plate.
11. Hooray! All the platforms across the wide chasm are moving. Step carefully onto each platform across to the other side, where a bag of Jellybeans and a sprig of Dittany awaits.
12. Now return carefully, over the wide chasm and other obstacles, to where the entrance of Hagrid's garden is. Finished!
"You found the Dittany! Its tiny fronds wave as if in greeting!"
Now you end up back in the Grounds, wherer Ron awaits. He tells you go ahead for Flying lessons with Madam Hooch. Go to the left of the Grounds, where there are two grey walls. Enter the new area for your Flying Lesson. You find out you're late, and Madam Hooch is taking Neville Longbottom to have his arm patched up - the silly git fell off his broom. Now Malfoy swoops in, and makes fun of Neville. Angry, you chase Malfoy on your broomstick and try to get back Neville's Remembrall, something Malfoy stole from Neville. This is when you will learn Quidditch.
Using the controls mentioned above (look in the Contents), chase Draco Malfoy and get back Neville's Remembrall. He leaves behind rings of sparkles that you have to fly through to get a speed boost. A yellow bar at the bottom of the screen fills up as you fly through more and more rings. If you get enough rings and are close enough to Draco, another bar will appear in the middle of the screen. You don't control Harry, just concentrate on using the A or B button to catch the Remembrall as it drifts along the bar towards your hand. This is when you have to catch the Remembrall, and you have a limited time to do it!
"You recovered Neville's Remembrall! Draco and his rough-hewn cronies will think twice about taking you on now."
When you successfully catch it...Oops! Madam Hooch has spotted you taking off, and she chides you. Just as you open your mouth to protest, she praises you unexpectedly about your skill of a broomstick and makes you a Seeker for the Gryffindor Quidditch Team. Then she tells you go back to your Common Room (Floor 7). She leaves, and as you turn to go, you spot Malfoy and his cronies! He tries to snub you, but you snub him back and he leaves, inviting you to a Wizard's Duel in the Trophy Room (Floor 3). Now go back into Hogwarts and proceed up the flights of stairs. Unexpectedly...