I feel as if I should contribute something here. Here's a couple of elementary tips on operation and some random thoughts:

Regarding "silence"--many players new to PSRs don't know that, when in a fingered acc mode, if you hit three adjacent notes in the chord section, everything stops except the drums. This is quite useful for doing exactly what Uncle Dave said. There are many songs that call for this (Land Of A Thousand Dances, What'd I say, etc.) and this is merely a shortcut to killing everything except the drums. Of course it doesn't work with one-finger or multi-finger modes.
Which brings to mind another point. It's easy when you first go to an arranger keyboard from another instrument, say a trumpet, to use the one-finger mode. Do yourself a favor, and spend a day or so learning to play the full chords. One-finger mode only recognizes a very few chords and will dramatically limit your progress in becoming an arranger musician. I'm not saying there aren't valid uses for one-finger mode, but it is essential to your musical growth to learn the chords.
Also, there is another side to arranger playing, especially for those who have limited right-hand skills. Let the arranger play. You can work with the volume levels on the individual style parts, bringing up, say a piano part for one song, increasing the guitar part on the same style for another song or a different section of the same song. Save your changes to registration. This adds variety to your repertoire. Be careful not to overplay the right hand. If you can't play something that is complimentary to the song you're doing, SIT ON your right hand and let the arranger do the work. Just play simple lead lines when the solo comes. As your skills improve, start doing more of the playing yourself, becoming careful to add to what the arranger is doing, not undermine it.
You will need to learn to think like a guitar player, or a sax man when using those instruments. Often converted piano players have a hard time adjusting to arrangers because they are not used to having the "help" of the arranger section. Either turn off the arranger, or use it to your advantage.
Another tip that someone MAY not know, on most PSRs and many other brands, pressing the + and - keys simultanously will set the selected parameter to the default setting.
For instance, each song has a default tempo, the transposer defaults to zero, the effects have defaults settings, and this "trick" immediately resets.
DonM