HTPC and speaker connections

[CooK1E]

Apologies for what will probably be quite a noddy question

I've got a HTPC with the following connections on the back

http://imageshack.us/a/img832/2003/fjls.jpg

And a set of speakers with the following connections on the back:
http://imageshack.us/a/img28/3650/pm7b.jpg

I've got a load of 3.5mm to 2xRCA cables for connecting the two, however I'm bloody confused as to where I should be connecting each lead to - can anyone help?

Also what should I be setting XMBC to once I've got it all connected up properly?

Thanks

 

[CooK1E]

Lovely thanks - would have seen this earlier but I'd set the thread subscription up wrongly! All set up and working

Ended up removing the rear speakers so have set XMBC to 3.1 which works perfectly