Hi @Loki_K,
The way it works is that we have a rolling window of 14 days going backwards in time from today at 00:00 UTC. You cannot make any more submissions if you have 6 submissions within that rolling window.
So, once your first submission is longer than 14 days ago, the first submission no longer counts against your limit of 6; then once your second submission is longer than 14 days ago, the second submission no longer counts against your limit of 6; etc.
Hope that is clear! Let me know if you still have any questions. Good luck on the competition.
EDIT: Updated to reflect that the rolling window does not move continuously but is always counted from 00:00 UTC each day.