on the d7f, its a really easy job, only has one camshaft, just a case of supporting the engine, taking off the left hand engine mount and timing belt covers, line up the reference marks, remove tensioner and idler, refit new ones, new belt on, tension belt, make sure marks are still lining up, refit engine mount.
Might sound like alot, but its actually pretty straightforward. Drivebelts are simple to change in the process aswell!