Following the link in the OP you need to go to Nissan, Xterra, then model year. The link you posted, for one reason or another, stopped working in the past and we had to go back to the link in the OP.I couldn't get to what I wanted following the link in the OP, so I did a search and came up with the following:
This takes you directly to the model year selection.
Follow the links listed below to a downloadable copy of Xterra factory service manuals and owners manuals (.pdf files). The FSM's are a much more thorough and detailed guide to both routine maintenance and repairs and contain any and all technical info you may be looking for.
A huge thank you to both NICO Club and Courtesy Nissan for making these available to all.
Select your model year and the appropriate section you are looking for.
Nissan Factory Service Manuals
Find and select your model and model year.
Xterra Owners Manuals