Monkeyvich:
Your questions have already been answered but my last advice it to do this: take a well made, mod with most sorts of modding involved and open that and just keep it next open when you mod. Also open the modding.pdf file of the latest version (do update to the newest version, no risks there) and then just try what you want, look it up in the "example" mod and then check it with the doc file.. most mods don't use all commands but most things not used are specific abilities for troops which are just #****** and that is all perfectly clear from the manual.
My advice would be to take Sombres Skaven mod (it's the one I used) as example, I know all sorts of modding is in there and it's organised in sections (weapons, armour, troops, commanders, sites, general nation commands) clearly so you can easily find what you are looking for (scroll through it a few times). Most of the stuff is clear when you've seen it once. Copying something and then changing it to whatever you want is possibly even easier (my first two mods started with copying Sombres lines for the start of the mod, nation settings (which are most annoying at start and then just deleting his describtions etc.. those mods all use the skaven color since I usually don't bother to change it
) then copy a random troops and just change his stats, same for commander. If you wonder what a certain command is for (though it's usually very clear) look it up in the .pdf file.
There are multiple strange things you can encounter but I don't know them all and it's not that big of a deal if something doesn't work then just come back to ask about it. The strange stuff isn't in any of the basic stuff you need to get a mod working though, creating a mod, starting a nation with some troops and costum weaponry should work (if you copy correctly)
Good luck.
Of course this has nothing to do with combining mods... I never do that
, I just make one big mod from scratch. (Check out my sig, dom 3K for a sort of wh 40K experience, if you want to help on an over ambitious mod there is plenty of stuff to do
)