How-to Missions.

In order to do Missions, you have to post, in that Mission, that you will Join.
Missions completed Will Give you Mission Points, which will be Updated as Often as Possible.
Here's a Guide to Missions and Mission Points.

D-rank Mission - 1 Point
C-rank Mission - 3 Points
B-rank Mission - 5 Points
A-rank Mission - 8 Points
S-rank Mission - 10 Points

Now, there are special Rules for some Missions.
Team Missions, the Members will Only get half the Points.
Jinchuuriki and Bijuu Missions will be worth Double Points (Most of these will be A and S ranking).
Assassination Missions are worth and extra 5 Points along with the rank of the Mission.
Other Missions will be determined by the Persons performance.

"Now then, as for the Rules about Missions... Tobi, Bring in the Chalk Board."