Are you active at all? Because if you're not, then just getting active again you'll lose some weight. But at your size, I'd highly recommend losing at least some weight before working on getting your muscle. I'm not saying don't use weights, but don't focus only on weights, focus mainly on cardio and modify your diet to cut down on calories.
I'm 6' 3" and I'm around 255 lbs. and I'm trying to lose weight and gain muscle, but I had some muscle before I started, it sounds like you're starting working out for the first time (or the first time in a long time)