The time and repeat buttons only work in software version 2.0 and later.
I recommend that you use software version 1.03 until the next beta is released. 1.03 is known to be stable and is a final non-beta version. The 2.0beta7 that's available has some known bugs, some of which are pretty serious.
You can do all of your MP3's at once, but I do not recommend it. It's better to do it in small batches. If you wish to do all of them at once, you simply drag and drop your entire MP3 directory onto the root playlist in emplode and synch. If you wish to do it in batches, then do it an artist at a time.
Make sure to skim through the FAQ at www.riocar.org
, especially the sections on organizing your MP3s and getting the tags straight before sending the songs to the player.