Need Help With Books

[trvlnmny]

I am new to Kindle. I have a Fire 5th generation.
It is mostly used for reading books.
When I go into Books I see 2 headings, one is All
and the other is Downloaded.
It seems that everything is listed under All either with or
without a checkmark.
Those with a checkmark are also listed under Downloaded.
I would like to remove the checkmark from many of the
books that are listed as Downloaded.
I see I can change a Book from All to Downloaded but I am
unable to change a Book from Downloaded to All.

Thanks for any and all help.

[Veber]

I want to find it too