if you're using the TWC packs, then:
A) Put the chosed packs into the data folder (..\Steam\SteamApps\common\Total War Rome II\data)
B) Remember to revert to the old manager: Go to Rome 2 on STEAM/Right click/Properties/Betas/Select the beta you would like to use/launcher_release_canditate.
C) Start Rome II
D) In Mod Manger, check "Enable Out of Date Mods"
E) Make sure all chosed packs are checked green. Their load order should be ok. It is given by the number of @, the more they are the more previous the mod is loaded/must be loaded
F) Play