A quick primer on how to add new items to Angband:

1. Add the item to objects.txt 2. Make sure limits.txt has the kinds limit set high enough

If you aren't adding a new tval, that's it. If you are adding a new tval:

1. Add the tval to tvalvals.h 2. Add the tval to the wizard menu in wizard.c 3. Add the tval to obj_desc_get_basename

That will get you basic item functionality. You'll probably want to do more hacking to get your item to work right, but this will get you up to "junk item" level.

Note that kinds are meant to be a 1:1 mapping from (tval, sval) pairs. So, don't rely on the game being able to distinguish between the same (tval, sval), even if they have different pvals, names, kinds, whatever.

Rumor has it that kinds will be phased out entirely.