SoTMK time given in TP

When adding SoTMK in TP it gives 20 minutes. Is this the time it takes to sign up, or the time it takes to do one mission?

From our experience, I would count about 10 mins for the sign up and probably 30 minutes for a mission.

Thanks! Is a mission just around one land? How many missions are there all together?

There’re 4 missions on 4 different lands:

-Main Street U.S.A.
-Liberty Square