Time to by a book then.
There is a mark on the Injector pump which lines up with a line on the block, the injector pump uses the same drive from the cam as the distributor on a petrol engine. You loosen the 3 bolts that attach the injector pump, the pump is then free to rotate as the bolts sit in slots. Move the pump Clockwise or Anti-clockwise either side of the mark to see which way the engine runs better. try moving it a bit one way , tighten it up, give it a go and so on, lots of trial and error.
All this assumes that you have'nt taken the Pump of in the first place and really buggered the timing up.