How do i flash my phone? how do i begin to load a new rom?

i have a htc evo and i want to add sense 3.0 to it like the 3d evo, but every youtube video i watch it sounds so complicated, like they say go xda developers and find a rom you like but first you have to flash your phone or un brick it? im like wtf is all of this ****? isnt there a program that does everything for you you just pick one rom you like and then it adds it for you? idk any help i guess