Firing Up My Gravity Feed Smoker

Newbie to the forums here. I've been a backyard stick burner for about a decade now and recently upgraded to a gravity feed smoker. The smoker is awesome and built solid like a tank. My question has to do with getting the lump charcoal lit and firing up the smoker. I must be doing something wrong here because I am getting a ton of heavy charcoal smoke whenever I start up the smoker and it usually lasts for a few hours. I have to open the door every so often just to let some of the charcoal smoke out and it plumes out big time. When I start the lump charcoal I fill the charcoal chute with the amount of lump charcoal I plan to use for the cook and close the lid. I then use my propane torch and get the coals lit from underneath in the firebox then close the firebox door and let the bbq guru take over - but when I do this for the next few hours there is just thick charcoal smoke coming out of the smoker. My question is what am I doing wrong? Do I need to leave the top of the charcoal chute open until the coals are really going and there is no more smoke? Am I not torching the coals for long enough from underneath in the firebox? They light up pretty quick so I usually only torch them for a few minutes top. Should I keep the cook chamber door open as well while the coals fire up? Any advice/help would be super appreciated. Thank you