I downloaded the trial version. I’m writing a novel. Is it possible to insert endnotes? The book I’m writing kind of requires them. Any help would be appreciated.

Sure thing. Just press Ctrl-Shift-F to start typing in the endnote, at the position where the numerical marker should be inserted, and when you are done tap that shortcut again to go back to normal typing. When you compile, these grey bubble ranges will be converted to proper endnotes (if the target format supports such a thing, naturally. RTF and such a good).

For full documentation, check out ch. 17 in the user manual PDF (pg. 127).