I cant figure this out

My name is Jesse, I need help with a couple of things, I’m a beginner at coding and to Playcanvas, but none of the tutorials helped. I don’t know how to make an inventory system, I could not figure out how to make a white dot crosshair system. and I don’t know how to get voices to activate when I need them to. and I can’t figure out how to get a gun animation to activate when I press “f”. I need help making a wall detection and a e to interact bool
please help