Watch these videos. Gives you instructions on removing the oil rail plugs, removing and installing injectors, and purging the cylinders with the glow plugs out:
Couple of things to note...... be VERY careful with those oil rail plugs. They can strip easily.
When installing the injectors, make sure they are bottomed out completely when you tap them in with the rubber mallet. I used a level to ensure that all injectors were seated equally and that none of them were sticking up higher than the others.
Purge the cylinders with the glow plugs out. That gives the remaining oil and fuel in the cylinders somewhere to evacuate so you don't hydrolock the engine. You can do this by putting the valve covers back on (only use a couple of bolts to hold them in place, finger tight is all you need), this will keep the oil from spraying all over the engine compartment. Also ensure that when you purge the cylinders that the injectors won't try to fire. Simply unplug the electrical connector on the CPS, or leave the injector harness unplugged. As an added bonus step that I do personally, after those quick purges shown in the video, I also did some extended cranking afterwards to evacuate a little more out of the cylinders, and also to start getting oil flowing back into the HPOP reservoir and the rails. Oh, and make sure the oil rail plugs are back in when you do this, and you can leave the valve cover gaskets (with wiring) out of the truck during this step so that the glow plug wires and connectors don't flop around freely while you're cranking. Sometimes the simple things get overlooked. Ya never know!!!
Also, if you want to triple check everything... after purging the cylinders and reinstalling the glow plugs, put the valve cover gasket back on and clip/plug all the wires back in to the injectors and glow plugs. Leave the valve covers off, plug in all the wiring (CPS wiring and injector harness), and crank the truck. Let it idle with the valve covers off and check to make sure the injectors are firing equally (watch the oil flow out of the oil deflectors, it should be equal on all injectors). Once you are sure everything works with the engine running, shut it off, reinstall the valve covers, intercooler piping, etc, and you're done.
Last, go drive the truck a good 30 minutes to get rid of all the smoke and purge the air out of the oil lines. It's going to have a white haze for the first several miles, then it will gradually reduce and go back to normal with no smoke. Also it's going to run rough at first. This is typical.
Hope this helps. And props to Maintain for those videos.
P.S. When cranking, make sure you don't leave any rags in the intake or turbo.