"Menu Press to access the menu and make selections. Use the Skip/Search buttons to navigate the menu. In Play mode, press to set the EQ or repeat settings. In Pause mode, press to access the local folder and delete options."
Ok this operation is the same with my ml961. I found this in the pdf download for your unit. Hole the menu button for a few sec 3-5 release you will be in a menu to set various features for music.
This should be in the manual that came with you unit. I had to go through mine a few times to find it Then I was looking in the wrong spots of the manual. I know a lot of us figure we can figure it out right off that bat but unfortunately GPX did not make that easy. here is the link to download the manual it is only in pdf 4GB Digital Audio Player MW353B GPX
Hope this is of help.