The three windows to start the league all have their own permutations. Read the following links for more info. The first link gives a brief explanation into the fixtures and how they work and the second is the list of fixtures.

https://www.englandrugby.com/news/article/community-league-fixtures-confirmed-pending-rugby-restart-date

https://www.englandrugby.com/dxdam/5a/5a5533a8-5099-4f9b-9d7d-8d8099c4f2fc/North%20Fixtures%202020-2021.pdf