congratulations on your new ride! You should add the relevant details about it to you signature line, so when you ask for help in the future people know exactly what truck you have.
The basic troubleshooting flow chart for your truck is:
1. good charged batteries
2. clean connection and good cables to starter
3. good starter, possibly upgraded to the later gear reduction type
Since you have it cranking over quickly we can tell all those things are in line-
4. Fuel in tank
5. lift pump working
6. purge air from lines.
7. make sure fuel cut off solenoid is working, has power to it.
The easiest way to check the lift pump is to push the schrader valve in on the filter head while the engine is cranking. It should spurt out fuel and make a mess. Don't get it in your eyes/use a rag!
If you have fuel there, then loosen the injector lines at the injectors and crank again. Keep cranking until you see fuel coming out there. Be careful of the plastic fittings and flexible lines underneath the hard lines. These are the injector return lines and if you look at them the wrong way they will leak. And worse they will leak air in rather than fuel out and you will be back here with a different, but more annoying starting issue. Consider ordering a return line kit and replacing all those o rings and lines as preventive maintenance
If you don't have any fuel coming out of the loosened injector lines the fuel shut off solenoid (FSS) may be disconnected or broken. The easiest way to check is to turn the ignition key to start and then disconnect and reconnect wire to it on the top of the injection pump. It should make a clearly audible click as you connect it. If you are having trouble hearing it check the wire with a VOM or test light.
Now at this point if you have fuel to all of the injectors, the solenoid is clicking, and the truck cranks over quickly it should start!
If it isn't you should check the glowplug system. There are a lot of posts about the early style glow plug system, and choosing the correct brand of glowplugs. Read the stickies!
Good luck!