Welcome aboard. I sell grills at Home Depot and I also have a Silver Smoker. I really love mine. I hope you will too. I put fires in both compartments when I cured mine. It may not really be neccesary though.
Do you have a good thermometer? The one sold at Home Depot by New Braunfels is a good one. What I really recomend is a Polder though. You can find them online. I got mine from eBay. I recomend the dual sensor model. It's a digital unit that sits outside the smoker with a cable running into the grill. One sensor goes in the meat and the other gives you the grill temp at food level. You can also set alarms on them. If your cooking beef and you wan't it medium rare, you can set the alarm to go off when the internal meat temp reads 145 and you will nail it just right.
Also, do you have a good woodpile? Horizontal smokers are designed for long slow low temp cooking primarily. They are very versitile and can also do higher temp direct grilling but you'll find its not as fuel effiecient as a Weber kettle if your just doing a few steaks. You could go broke feeding it charcoal briquttes. Get some whole logs or logs cut into chunks. They taste better anyway.
Also you'll need at least one chimney starter. Since smoking and roasting takes hours you'll be replenishing your coals about every hour. There are some threads on this already.
See "How to add charcoal"
and "Green Wood or Dry Wood? Ginger or Mary Ann" for starters.
I hope you find it as much fun as I do.