Take both speakers and mark the same terminal on them....this will be your positive. It doesn't really matter which terminal you choose as long as it is the same one on both speakers.
Next decide if you will wire them in series or parallel. If you are using 8 Ohm speakers (you should be) then series will present a 16 Ohm load to the module, which will then output 0.5 watts of power to drive the speakers. The sound will be quieter, the amplifier will not be working as hard. If you wire in parallel you are presenting a 4 Ohm load to the module, which will then output 2 watts of power. The sound will be much louder and the amplifier will be working harder.
See this link for explanations and diagrams:
http://www.bustedgear.com/faq_Speaker_wiring.htmWhy would you ever wire in series if parallel is always louder? The answer has to do with your speakers. If the max watt rating on your speakers is 1 watt and have them wired in parallel, you have the potential of overdriving the speaker up to 2 watts which could damage or destroy the speaker. If you have speakers that are rated for 2 watts then go for it. If not, parallel is probably safer. Plus it will be plenty loud.
I go back and forth between the two methods depending on the type of speaker I am using in a particular install. In the end I normally turn my sound down to a level that is not obnoxious.
-Kevin