How to divide this plane to delete or colour in the four big islands?

Stupid question probably
But haven’t come across this in a long time
I designed this outline for a path that goes around four major
spaces green or what ever it will be
I can’t figure out after tracing all the patterns
how to separate the walk ways and four major spaces
In the beginning it was fine
but then I added one circle for a tree or bench and suddenly all filled up.
I did not go back immediately and now can’t figure out how to reverse it.
Thank you.

You should make groups or components of the different elements on your model, if you have loose geometry the edges from one element could get glued with other elements.

While awaiting a reply I had started to by deleting the entire plane then
filling out what I needed to remain as a walking path.
So thank you very much I managed with making this by making two groups
the centre and outer frame
Still some issues to delete the dividing line that I made to fill the plane
as often everything seems to fill areas again.

To help achieve your goals, some time spent at the SketchUp Campus and at the SketchUp - YouTube channel will be very worthwhile. Both sites are from the SketchUp team. On the YouTube channel, pay attention to the Square One Series. It covers the basics for each tool.