Help for Desktops?

Okay, I'm tryingt to figiure out how to use the Desktops feature for the first time, and finding it to be about the least intuitive, worst Apple featurew I've encountered in 25 years as an Apple user.

I can't find anyplace that provides a simple explanation of how its supposed to work, and how to make the best use of the feature. All I get are thrilling notes about how I can SWIPE between them. I know Apple likes to avoid giving directions, but when the product is this opaque, you have to throw a guy a lifeline.

From what I can see, the desktops aren't really different. All the crap on my first desktop appears on my second desktop, and if I move a document on the second, it also moves in the first.

Sometimes I accidentally drag an item and my screen rolls over to the next desktop on accident. Other times I try to make that happen, but can't make it happen. Where can I find directions?

Once I successfully dragged an application window to the second desktop so I could work on it there. But now when I click on the same application in the first desktop, it whips me over to desktop #2 whether I want to or not. it's whipsawing me all overthe place.

I notice in this application there are settings for "Ignore desktops" -- do have to go through and set prferendes for every single piece of software on my imac in order to use this feature?