In an International Round Robin, there are 6 participants, each person makes a centre, then sends her centre to the next person, who adds a border. Then it's sent to the next person in line, who adds another border, and so on until each centre has 5 new borders, added by 5 different people. Then the completed top goes back to the person who made the centre, to be quilted and finished by them.
And yes, it always gets sent by you, to the same person in your group each time it's due to be mailed.
There is a timetable for this.
Hope this helped.