er, i was going to do a guide but haven't had time really. I could run through it but its not so easy to explain in type. Its not that difficult, but some experience etc is useful
At that mileage, its gonna need servicing to be honest. Best case scenario is that it you get it done and its fine for the next 30,000-40,000 miles.
Worst case is that its pretty worn inside and new charger time!!!