With a propane smoker, it's next to impossible to keep the temps low, for example to hot smoke salmon.
I have a 38" Smoke Hollow which comes with a large chip pan. When I want lower temps, I place coals in the pan, use HIGH to start the coals, then turn off the propane. I then put wood chunks, not chips on the hot coals.
How many coals you need depends on local temps, winds etc. and your smoker. Don't get carried away. Get or make a chimney type starter and keep a few extras lit. If your smoker is too cold add one or 2 more, if its too hot, vent by slightly opening the lower door (if you have one) or use tongs and remove a coal or two.