97 A6Q timing belt question

[walian at att.net]

Hello all,

    Doing alot of work on my A6 this weekend. I am
replacing the timing belt and have a question with
regards to the bently manual. I rented the timing belt
tools and am wondering why I need to take off the cam
sprocket. (13-17 bentley) Do I need to loosen the nuts?
The picture shows the puller pushing on the nut is this
correct. What am I missing here? I know there's gotta
be a good explanation. I just can think of one. Am I
suppose to completely remove the sprockets?

Thanks

Frank