I'm stuck at the part were you have to escort prince Ralis and I just can..

I don't quite understand what you are saying. Do you mean the whole quest or just certain parts of it? I'll still help you though, but it will just be a really long walkthrough guide, so brace yourself. Once you read all of this, I hope you understand how to complete this quest, which will unlock the Zora Tunic needed to get to LakeBed Temple at the bottom of Lake Hylia.

After watching the cutscene, ride your horse and follow the carraige. Make sure not to get ahead or go too fast, as that will result in enemies in damaging the carriage more easily. Only use the dash-moves (those 5 icons at the bottom of the screen to boost your speed) when you are falling behind. For now, equip yourself with a Gale-Boomerang to put out any fires; Hero's Bow to take down any enemies from a far distance; Bombs to take down enemies from a closer range and to produce bomb arrows; and finally a bottle filled with Red or Blue Potion to heal yourself. Now just ride your horse all the way to the Great Bridge of Hylia to continue.

You will now end up in another jousting-like battle with your little friend you battled before: King Bulbin. This time around, he has two wooden shields equipped on his shoulders to protect against your sword attacks. Just like before, charge towards his boar, and at the last moment, quickly evade to the side. As you'll notice, you can't hit him from the side, so you're only option is in the front. Midna will tell you (so you won't need to think) to take out and use your Hero's Bow to hit him. Now things have become very easy; now all you need to do wait for him to come to you and then shoot him in the face with an arrow. Get out of the way and repeat twice more to defeat him and claim two keys.

This is where things start to get challenging. Follow the carriage and be sure to stay close to it so you can guard it when the time arises. You will soon be greeted by several Archer Bulbins that will shoot fiery arrows at the carriage. Defend the carriage by shooting down the enemies with your bow & arrow and using the boomerang to take out any fires. When you reach the locked gate, hop down your horse and open it with your keys to continue. Now things will get extremely difficult from here! Before you go, make sure you equip bomb arrows for devestating results to your enemies.

You will be then be ambushed by a horde of Bulbins riding wild boars. Quickly kill them all simply with your sword; use spin attacks and combos for best results. Then a flying inosaur enemy will fly in front of the carriage, hoping to drop a bomb. This is where you need to be serious! Quickly take out your bow and shoot it with bomb arrows to take it out before it drops the bomb. Or even use the boomerang a couple times to detonate the bomb to kill the dinosaur enemy! Just make sure the bomb doesn't drop or else the carriage will spin out of control and you will have to defeat the boar-back Bulbins and the dinosaur enemy again!

Once you actually manage to do that, quickly take out any fires with your boomerang (if need be) and continue taking down Bulbins on boars. You will be ambushed by a couple more of them, but not as much as before, so it will be much easuer. Take them down and defeat the last remaining dinosaur enemies before other bombs get dropped to safely let the carriage into the village. Remember to put out any last remaining fires with your boomerang. Hop down, open the gate, hop back on, and ride your way to victory! Your reward will be the Zora Tunic needed to get to the LakeBed Temple.