Your Passive is Pix, the little fairy.

You can give this little thing for a short time to allies and enemies with your E.

When it is on your allies, it will help them to deal more damage for the time it is on them.
When you put it on your enemies, you will get true sight on them.
When it is on yourself, you have the little extra damage you give to your allies.

When you activate your Q, you and Pix (the Passive) will shoot a magical shot to the direction of your cursor.

If it hits, it will slow the enemy and die a little damage to them. Use it to poke the enemy and help your ADC farm and push the lane.

When Pix is on an ally or an enemy, it will shoot from its position.

This small spell can give movement speed to you or your ally or polymorphs an enemy.

The movement speed is really helpful when you are chasing or getting chased - i can help you or your ally to go in a fight or away from a fight really easily.
The polymorph is helpful when you are in a fight. Cast it on an enemy to stop him from dealing damage. It is really helpful when casted on the one with the most damage, to keep you and your team safe.
You can use your W to get yourself or an ally faster to his lane.

It can shield an ally or damage an enemy. If casted on any champion, it will give them pix.

When you cast your E on yourself or an ally, he will get a shield and pix for a short time. Pix buffs the dealing damage.
When you cast it on an enemy, he gets damage and Pix. Pix will give you true sight on them for a short amount of time.

Your E is really helpful in fights to keep you and your allies safe from some damage.

Your R can be casted on you or your allies.

It will knock up every enemy in the marked circle around the ally right after you casted it.
You or your ally will get bigger and gain extra 300/450/600HP. Your ally will deal more damage too.

If you or your ally are full HP, it will still add the 300/450/600HP, but the HP will be taken away after the Ult expired.
If you or your ally are not full HP and there is something of the 300/450/600HP left after the Ult expired, the one who had the Ult keeps the extra HP.

You can use your Ult in teamfights at the frontline to knock up the enemies and make it easier for your allies to kill them.
But it can also be used to safe a life: When you or your ally are low HP and need some health really quick, you can cast it on them so they will get the 300/450/600 extra HP.

You are an easy target for enemies - so try always to stay safe at a tower or with an ally.
Don't walk alone trough parts where you have no or not much vision - it's too dangerous.

Just have fun with Lulu - she's not that hard to understand and you will get the clue after a few tries.