I was going through the how to get started thread and got to this step:
I had a bunch of things available (@ace, @acex, @ACEX_SM, @CBA, @TGmaps) but not @tgmodpack. Not sure what to do at this point.
A window titled, "Modset configuration : (Tactical Gamer)" should have popped up. On the left, check-mark the box next to "@tgmodpack", and then enter "Modset name" in the middle-top box with something like "TG Mod Pack". Click "Save" in the bottom-right, and you should be back to the "Launch game" tab.