Have a look at this thread, and the threads linked to in it. You'll get a few examples there and instructions there.

 

Yes, I linked to this guide in the other thread. It explains priority. Basically, when two or more profiles' conditions are met at the same time, the profile with the highest priority activates. So, if you have a profile set to underclock above a certain temperature, that should have a priority of 100. If you have profiles set to underclock in steps as the battery goes down, you want the priority to get higher as the frequency gets lower. Basically, if you have profile to underclock, say, ~800 MHz under 60%, you can give it some priority (e.g. 60). Then, say you want a profile to underclock to ~500 MHz under 30%. That second profile has to have a higher priority (e.g. 65). Reason being that the conditions for both (under 60% and under 30%) are met at the same time once the battery is lower than 30%. You want the lower of the two to be active, so it gets a higher priority.

Those are really the only two hard fast rules on priority. Beyond that, you'll probably want a power plugged in/charging profile with a priority of 99, and a screen-off profile set to 98. Anything else is up to you as to when you want it to take effect over other profiles.