Newbie! Access to files for members

Hi I can’t find this info anywhere and I’m going round in circles! I have a membership where members get two files each month. So, a member joins in march and gets files 1 and 2. A new member joins in April and gets files 3 and 4. Does March member still have access to 1 and 2 and April doesn’t? If yes how do I set this up?

Thanks - apologies if this is a stupid questions!