See DomoKuns post earlier in this thread for the content of the script;
substitute your own pcm-files as suitable. Note that the line
let "number %= 7"
uses 7 as the number of files you have. But the case construct goes from 0 to 6 as that is what the modulo operator (%=) returns.

Use a text editor that can save a file with unix style line endings, like EditPad or UltraEdit

Upload the file to a suitable directory, for instance /drive0/var. Then make the file executable (most GUI ftp clients have a graphical way of setting the rights. try right clicking the file on the empeg and look for "rights" or "permissions"). You need at least read and execute rights for owner (500). Typically you can use 755 (read/write/execute for owner, read/execute for group and others).

Edit your config.ini file and add a call to run your script. If you placed it in /drive0/var and named it randomsound.sh then it'll look like this
;@EXEC_ONCE /drive0/var/randomsound.sh

/Michael