A “bookmark” saves your place if you’re listening to an audiobook, stop and want to got back to that same place later.
If what you are asking is if there is a way to automatically go to a spot in a file and start listening, then in this case you would have to press and hold the FF button until you reach the point at which you want to start playing the file. Unfortunately, on longer files (such as audiobooks tend to be) the counter really isn’t that accurate.
