If your friend did not have the basic recipe book for it, you can go to their website.
http://www.brinkmann.net/recipes.aspx
Most critical things on any smoker is temperature, time, & moisture. Like they already said, make sure the water pan does not get empty. Baby back ribs are easiest to start with, usually takes 3 1/2 to 4 hours at about 210 degrees. Keep them on the middle to upper racks to where most of the smoke & moisture will be. For this short time duration, the water pan normally will not go empty.
Most smokers, even the same brand & model, will be a little different, mostly in controlling the temperature by use of the air coming in & going out without putting out your fire or over cooking your meat or cooking too fast. If you cook a lot of ribs, you may want to rotate the top & bottom racks about 2/3 the way through and you will have to extend your cooking time.
Patience - practice makes perfect but soon you have a finished product better than you can buy at most restaurants and cooked & seasoned the way you like it.
Note: don't open the cooker anymore than you have to, because it will take a while for the temperture to come back up. I will do a quick peek towards the end to see how longer it will take and may even cut into it on larger pieces of meat.