First set it on smoke. Once your hear the fire set it to about 250. Gradually work your way up to 400. The lid thermometer is not accurate always go by the digital read out. You can also place a temp probe (you have to buy one) on the grate and check the temp there. You have to remember heat rises and the top where the thermometer is will have an inaccurate reading.
I finally realize that the hood temp gauge is not accurate above 350 degrees. I was using my PB1100 and Yoder cooking pork butts @ 250 to do a comparison and I notice the hood temp on the 1100 was right on the money it at around 250.
When I increase the temp 400 to burn off the left over on the grates it was reading 525 so I have a feeling that the hood temp gauge cannot handle the high heat. So I like to do crazy stuff so I took the hood therometer off my Yoder and placed it in the PB. Turn the PB on as normal and them cranked to 400 and what do you know the gauge was at 405 - 410. So I order a better lid thermometer today for the PB.