Lexus650

Can anyone on here explain to me how i go about replacing my valve covers im no mechanic but im tired of paying other people to do ****ty jobs so i wanna take the task on myself i already looked it up and noone really seems to explain it well my gs has a horrible leak it leaks a lot especislly when i go fast in it and when driving you smell the burnt oil sincr it falls onto the manifold im guessing ?it was leaking when i bought it and it leaks real bad i need help if anyone would be willing to help me i already have the manual but i dont understand it too well any help is much appreciated