Since you are a newbie, I strongly suggest starting with pack, for two reasons:
Precisely what you mentioned - in the docs and tutorials, pack is used. In the beginning you will work a lot with tutorials and docs, so it's better to have a common language.
Pack is the simplest manager in Tk. Use it until you find it limiting (I *still* haven't found it limiting, except for singular cases where grid is an obvious solution). Once that happens, move to more complex managers.