If you want to hold a special session (e.g., a review session before an exam or help session on a difficult topic), then you should ask your students when a good time would be and schedule a time during the day with MVis. If you need a larger room, someone needs to contact the campus office for room reservations. This someone does not, however, need to be you. Ask Frankye about room reservations.
It is generally not a good idea to schedule a special session in the evening, because many students commute and will not be able to come. If more than one TA is assigned to your class, you may consider holding multiple sessions at different times to allow more students to attend.
Even if you are not be required to hold special sessions, you may decide to do it if many students really need help and you have a little extra time.