any twitch mains can help me?

Not a twitch main but I adc a lot so I can at least help you out with the basics

are two main core items. You use these for assassination and peel/kiting in fights. Always save your yoummu active for right before you ult.

When assassinating a target it's pretty easy, just stealth up to them, W + Botrk to open up, pop yoummu and destroy them.

When preparing for a teamfight, wait until you see a likely initiation and pop your Q. Walk around until you find a safe place to ult from where you can hit the max number of targets and then pop yoummu and ult from there. You want to be in a place where you don't have to kite much and try to hit their backline with your ult shots.

Twitch doesn't kite very well so it's really important that you position well and use your stealth to pick off squishy targets.

Outside of botrk + yoummu, you want to pick up as your 3rd or 4th item, with as your flex pick depending on the situation. Last item I think needs to be most of the time because it's hard to avoid taking at least some damage as twitch and the spellshield + hp really helps a lot.