before thinking of importing your own models into fpsc, you should learn the basics with the stock-media, looking how its build, look at how fpsc handles objects using fpe/fps-files and scripts, learn basic commands in script language, and THEN think of how to setup custom media to get it running in fpsc. maybe you are able to convert and import your model, the next question will be how to setup the gunspec, how to change huds... you should really first train and learn fpsc-basics with stock-material.
but in short for entity weapons: build vweap-x-file and texture-dds using 3d-crafter (i looked for it, PLUS and PRO exports x-files), then build a gunspec, huds, set the gunspec with animframes, sounds etc. and ... try to use it. sounds easy, but its not for beginners, especially that every 3d-progRAM uses other export-routines that may not work directly with fpsc.
use google-forum-search at the bottom of each page to search for tutorials, there are more than enough in here to learn these things over time. look into ched80s script syntax list to learn the commands (sticker in the script-section).
