You will be promoted to member L2 when higher admins think you deserve the rank. You can prove you deserve it by being active on both forum and server, being nice, follow all the rules and so on.
Once you're member L2, you can ask to be a moderator (when you're in the clan for at least 2 months).
For all promotions you need to prove you deserve the level, and never ask for it. When you ask for a level, you will certainly not get it