For electronic questions like this i would refer to either the user manual or consult a trained and licensed electronics expert, as there are many types, and this is broad.
When you go on craig website it should of given you a specific models for the manual that you're downloading. Locate model number and go on back of mp3 player and match it to the one on the website. From here you should have the correct manual.
When you go onto their website it should give you specific models for the manual that you are downloading. Simply try to locate the model number on the back of your MP3 player and match it with one on the website, this should ensure you get the correct player's manual.
Manuals will have a list of model numbers that they correspond or relate to. your mp3 player will also have a model number on it somewhere (check under the battery) if they match then the manual is good for it.
