Are you trying to replace the timing belt or just check and adjust the Ignition Timing?
I have the Haynes Repair Manual #90010, which is for the Suzuki Samurai/Sidekick/X-90 and Vitara, Geo and Chevrolet Tracker, 1986 thru 2001.
You can get one at any Advance Auto, Auto Zone, about any auto parts. I find that it is invaluable with the information and data.
It does cover both Checking and adjusting Timing to Timing Belt Inspection and Replacement.
It cost me about $16.00 and well worth it!