NOOB Status

OK so I played Warband Vanilla with the Decap mod and kept getting errors so I switched to vikings cause decap is an option built into the game. I understand the game different from vanilla. I am playing the sandbox mode because I enjoy doing my own thing. But I am getting very frustrated starting with a longbow and dagger and not being able to find an option to buy weapons from cities....am I missing something here? Super noob question I know.

I started in Northvegar if that helps.

Which cities are you checking? The only "cities" with shops in them are the very large towns (think Praven or Sargoth). Norway's only got one: Tunsberg, on the southern coast.

^ What they said. ^
Most of them are ports, which still count, obviously, but there are a few non-port major cities. These are most notably in Britain.
I don't think there are any non-ports within Norway, Denmark or Friesland. You can buy weapons the same way you do in vanilla, by clicking "Trade with locals," in any type of major city (the font is larger than the villages,) and trading with the arms dealer. Hopefully this clears things up.