The user manuals are not very helpful but there are different ones available in the downloads section -
http://www.mympxplayer.org/documenta...anuals-dc5.htm
At least most of these manuals are in .pdf format so you can read them on your pc and increase the size of the text.
The basics - connect the MP4 Player to your computer via the USB cable, a window should pop up giving you options, select the folder option that allows you to view the contents of your player.
To put music onto the player just drag or copy it to the same location as the exising music, in the music folder.
You can drag photo's onto the player in the same way but into the picture folder ( once you get used to it, you can reduce the size of the pictures so that they load quicker onto the screen)
Video is loaded in the same way again but you will need to convert them to the format your player accepts.
Install the software from your mini disc, it will probably be an AMV Converter which is straight forward and if not you will find lots of how to guides on this forum, just search or post back if you get stuck.
If I knew what player you had (details and photo) I could probably be more helpful.
Douglas