Hi. The answer to your question to be honest is Don't!! If the belt broke it probably means there will be some internal damage to the engine, unless you are very very lucky!! To set up the timing correctly you will need a kit of stop pins. One for the crankshaft, one for the camshaft and one for the injector pump. The cambelt is not too horrendous to fit on a healthy engine, but in your case if the belt has shed its teeth then you will have to make completely sure there is no debris left around the pulleys, in particular the crankshaft pulley. Check also the water pump, check it turns easily and there is no side to side movement or nasty noises when turned. One other item to check is the jockey wheel, replace it if you can, if not check as the water pump for noises and free turning. Once you have the new belt(and I advise new tensioner) fitted and the timing correct, double check you have three stop pins in your hand!! (nasty if one is left behind!!) and the crankshaft pin plug is refitted, (messy if left out!) Try cranking to see if you were lucky, it may take a bit of cranking to actually fire up, but be ready for lots of noise and engine shake, not to mention smoke! It will be quickly obvious if anything is amiss.
If you find there is damage, my suggestion is to find the best engine you can afford second hand, fit all the new parts you fitted on your old engine to the new engine when it is out of the vehicle, (so much easier) then drop the new one in ready to go. Of course the other way is get an engine, fit new bits as above and swap them over, thus avoiding all the work to find out what will probably be the inevitable!
Paul
January 2008