1992 Ford Tempo timing

Engine Mechanical problem
1992 Ford Tempo 4 cyl Two Wheel Drive Manual? Miles

PLEASE HELP 92 tempo turns over but wont start gets fuel / spark just died going down the road. How can I check the timing? Or any place on the web that tells how to replace the timing belt (so I do it right) I have checked plugs, fuel filter, pump, cylinoid ect. When the motor turns over I hear a quite boof sound from the exuast area every couple of seconds (when it fires?) Just wont start am I checking everything I think changing the belt is going to be a big job so I just want to make sure thats whats wrong. Thank you, mike