It was a battle, but I think I've figured out SlimX bookmarks. I'm using the latest BIOS, 2.02. The latest manual is WRONG! If you read it carefully you will notice contradictions, but you use it anyway. What else can you do?
You have to have Study Mode active, IOW, not OFF. You set your first BM by long-sliding -10 until you hear a beep. You release and quickly short-click the Prog/EQ button. You will hear another beep and your first BM is set. Any time you want to set the 2nd BM, you do the same thing. The next BM is #3, the next #4, etc. all the way up to #20 if you want to go that far. If you've just set #6, say, and you want to navigate to the last BM (#5), you long-slide -10 until you hear a beep, you release and then quickly short-slide the NAVI/MENU control to the left. You will hear another beep and the unit will stop, search for the location, load the buffer and begin playing at your BM location. Realize that no matter what you do with the unit then, as long as you have the same disk in there, as far as the unit is concerned, the last BM you accessed was #5. If you want to do any further navigation with bookmarks you can go two ways - to BM #4 or BM #6. Moving to the next BM is the same as the last BM except that you short-slide the NAVI/MENU control to the right. This BM navigation scheme doesn't care where you are in the disk.
To delete bookmarks you have to realize one thing. You can only delete from the last bookmark regardless of where you are in your listening experience on the disk. The last one in is the first one out. IOW, if you have 14 bookmarks, you may have just navigated to your 4th BM, but if you delete a BM, it will be #14, the LAST one you entered. You can delete several bookmarks at once, but if you delete, say, 4 bookmarks at once, they will simply be the last 4 you entered. The procedure for deleting bookmarks is to long-slide -10 until you hear a beep and then release and quickly press MODE/FM. You will hear another beep and your last entered BM is deleted. If you quickly press MODE/FM several times (say N), that many of your bookmarks will be deleted (in this case the last N entered).