It's not very convenient to have all the bookmarks mixed up - soon, you will get lost in them. Thus, in ELinks you can categorize them to various folders, subfolders, subsubfolders and so on, then you can expand and back enfold them and so on.
In order to create your first folder, use the button Add folder and fill the
first input field. You can safely ignore the URL field, ELinks will do the
same. POOF and you see it - it has that strange
[-] thing there.
If it has
[+] near, it's enfolded, while when it has
[-] near, it is
expanded, while you can change that by pressing the spacebar.
In order to add a bookmark into a folder, move on the item of the folder (it must be expanded) or onto any bookmark inside of the folder and simply do the usual Add bookmark job. You can also move the bookmarks around, obviously. Before pressing the Move button, you need to first mark all the bookmarks (or even folders) you want to move using the Insert or * key—asterisk will appear near of all marked bookmarks—and then move to where you want to have the stuff moved to.
Separators can be inserted as well, using Add separator button, or by entering a special bookmark with "-" as title and no url.