Posted: Sun Oct 24, 2021 8:45pm
You're not being stupid Lindaanne, it is somewhat confusing to understand the way it works but, once you suss it out, you'll be fine!
From the day you step into the Schengen zone, over the duration of the next 179 days, you can only stay for a total of 90. These days can be split up into however many breaks you need, but must not exceed a combined total of more than 90.
The 180-day period keeps rolling. Therefore, anytime you wish to enter the Schengen, you just have to count backwards the last 180 days, and see if you have been present in the Schengen for more than 90 days throughout that period.
Below is the link to a Schengen calculator, I think this has been uploaded by numerous people, just open iy up and have a play about by inserting dates, fictitious or true, just to get a feel of how it works
https://www.schengenvisainfo.com/visa-calculator/