You should post messages regularly. By doing that, you will increase your activity. You will be Jr. Member when you reach 30 activity. After that, when you reach 60 activity you will be Member. After being Member, you will need merits from other people to increase your rank. Activity will not be enough to increase rank.
so
i just need to make 30 activity only by posts? and i will growing up?
That's not enough dude, try to understand what @DdmrDdmr says. Read this once again!
Whoopsie here: You need merits way before, not once you’ve reached Member rank. Each rank from Jr. Member onwards needs merits (OP’s next goal), being the Jr. Member requiring 1 Merit (and 30 Activity).
Read through the links provided by @evgenia_volkova to begin with, and then just explore the different boards to find those that are more appealing to you.
The earning part is really a phase II in any case, unless you can provide some skilled services from the start.