Given that you have a Summit Charcoal that you use for both grilling and smoking, it all depends on what you are cooking/how you are cooking. For grilling, fire the gas assist, get the coals hot and throw your meat on.
For smoking, you want the temp to stabilize for the most part. Fire up the coals (whether you use the gas assist or a chimney.) Get it running. Set the vents to try and reach desired temp. But again, don't be so concerned about a specific temp like 225. If it settles in at 240ish, that's fine. Even with the "settling in", the temp can wander a bit in either direction. The only time to really be concerned is if you get really wide temp swings, like it was at 225, but suddenly you see that it's over 300.
Check out this vid from Dickson BBQ on setting up to smoke. FWIW, you use the bottom damper to make biggest adjustments to temperature. Use the top damper to fine tune.