When creating a mission, it is important to amend your Terms & Conditions to reflect exactly what you want your ambassadors to do. They should reflect the mission actions and what your users must do to get their reward.
For some simpler missions, such as inviting friends or making sales, the T&C's can be fairly generic, such as 'Must invite X friends', or 'Must be X separate sales'.
For more complicated missions however, such as asking for content or sending out freebies, you can change the T&C's to tailor the exact content you want from your ambassadors. This can range from specific instructions, content quality, and any other distinct features you want the mission to have. Whatever you like!