I just looked at the procedure to line up the timing belt and tension the belt correctly and thought I could describe step by step how to do it but If you are going to do the work your self you really need to get a workshop manual or you can get a one year subscription to the same information a majority of independent repair shops use :
http://www.alldatadiy.com/
Alldata gives you access to repair information, wiring diagrams, technical service bulletins, component location and much more for a very reasonable price. They have a sample car you car look at on there website. Having the proper information makes doing the job so much easier and much of Alldata's information is straight from Audi
manual and ensures you have the information to do the job right.