All support for iRiver can be found their site:
The direct download link for the English manual in zip format:
Right click the link above and select Save target as, to save the zip file onto your computer. After the download unzip the file with winzip or winrar to see the manual in pdf format.
On top of the player there's a cover. The micro SD card should be inserted behind the cover, upper side of the player. On page 14 and 15 of the manual is told how to use the micro SD card.
Card insert: only push in or push out when the player is switched OFF !