How to design my cube?

I'm very new to SSAS and have issue planning a solid shape.

table 1: shut tickets with: ticket_id, user_id, date, processing_time

table 2: client information: user_id, login, first_name, last_name

table 3: client gatherings: group_id, group_name

table 4: time of client have a place with a gathering: user_id, group_id, assigned_date, left_date

I additionally included a period table

How would I plan the solid shape to get the measure of tickets a client has shut while he was an individual from a predefined gathering? I do not understand how to advise SSAS to choose the gathering when the chose date is amongst assigned_date and left_date.