The operation method of bookmarks is relatively simple

First, stay on the PDF page where you want to add a bookmark, and then click the first "Bookmark" on the left toolbar, and it will open In the bookmark panel, right-click the blank space and select Add Bookmark.

Generally, the default page is the name of the bookmark. We can double-click to modify it.

Bookmarks that have been added can also be modified through several function keys on the panel