1) That's the easiest way. Use a Y-splitter from the center pre-output, connect it to the different inputs on the PA-2000. Connect the 2 outputs of the PA-2000 to the 2 terminal pairs on the speaker. Just don't forget to remove the metal strips between the terminals on the speaker before connecting anything.
2) If you have the PA-2000 bridged, refer to the manual of the PA-2000 to see which terminals you have to connect. This must be exactly right, or you'll end up reversing phase or even destroy your equipment.
LARGE and SMALL has to do with the size of your speakers. It's quite easy. If you have large speakers (this means full range, usually floor-standing), set it to LARGE. If you have smaller speakers (bookshelf type for instance), set it to SMALL. The amplifier then will distribute the lowest frequencies of the front and rear channels to the subwoofer. If you don't have a subwoofer you'll loose the lower frequencies if you set the speakers to SMALL.
