Hey........I just purchased a polk psw111 to set up a 2.1 ch system. Room is midsized and I'll use this set-up mainly for music listening (obviously)

I think I want to make connections using the speaker level ins/outs, but I have never done this with a sub.
So my questions are.....

1. Is this a recommended connection for listening to music
2. What's the proper way to make this connection
3. Is there any down side or caveats using this connection [ie: setting mains / filter / crossover]

Thanks for any help you can give