to become merv or join a faction?

To become merv --- either run missions for him ( you get these after a few zion missions from tyndall ) or have a merv recruit you to his faction then leave the faction.

To join a faction --- visit the server thread of which you are playing, there are some quality merv factions. There are heavy RP factions, PVP factions, ones that do both and ones that just play to have fun

Regardless of how you doit to be a Merv you have to have positive merv rep, so start running missions. Doing Archives will not get you rep only regular missions and criticals will.