starter in 2000 XJ8 doing click and finish , ive check battery is good, and now i must change starter, maybe anyone do this and can say how ?

 

The process of swapping the starter out is detailed in JTIS available to download here,
https://www.jaguarforums.com/forum/x...archive-65998/

or pdf manual here,
https://www.jaguarforums.com/forum/x...at-x308-81022/

Before changing I'd certainly check a few power points first,
The black high power cables and their connections that run along the inside of the front fenders or wings, lift the bonnet and locate them - one terminates on a brass bolt on the brake servo cover, the other runs to the fuse boxes on the other side. Check their terminals and clean them up.
The earth strap between the engine and body underneath the car, and the earth terminal in the boot. Also the Mega fuse terminals behind the spare wheel can get bumped if the spare isn't tied down.