Kalua Puaa, it sounds like you are using a Weber Kettle. I cut my teeth smoking on a Weber Kettle, one of the most versatile backyard cooking appliances on the planet for grillin', smoking, pizza, you name it.
When folks first get started smoking everyone thinks "low n slow" with a constant temperature. One huge advantage of low n slow and constant temperature is a predictability window when the meat will finish. There are folks who are solidly in the camps of low n slow (long time), hot n fast (much quicker finish), and everything in between. Me? I look at my outdoor gear as a smoky oven. I grilled and cooked indoor for decades before I started smoking and never went below 325F. Had tons of delicious meals of beef, pork, poultry, and lamb. Cooking/smoking works at just about any temperature with time being the major factor. On my smokers I've smoked low n slow, hot n fast, and allowed temperature swings up to 100F. It all came out good. I'm pretty much in the hot n fast camp nowadays. Bottom line, have a minimum temp you want to maintain and don't sweat it if you see a 50F increase. Make an adjustment on your vent and it will come back into line eventually.
Now, controlling temp on the kettle is fairly easy. You can use either the bottom or top vents to control temp, but the bottom vent is best, especially when you are new. I make my fire off to one side, put the lid vent on the opposite side of the fire, then just add coals when the existing ones start burning down (get one of the grills where you can flip up the sides). When it is time to add more coals just take off the lid, knock the dust off the existing coals, and add new ones. You can add hot or cold coals, up to you. Don't be surprised if you see a large temp spike when you remove the lid. Adding lots of air to a fire stokes the hot coals. They'll come back down with a vent adjustment. You can also minimize the swing by keeping the lid off as short a time as possible.
You can buy a Nomex seal for the Kettle. It really isn't necessary but it is available.
The Kettle is a quick learn, as is the WSM. I still use my Kettle all the time, especially hot n fast.
Have fun. You'll have it mastered in no time flat.