Hi and welcome!
When I started, I was 340+ pounds, and in the beginning I opted to dive into a juice feast, which meant I drank juice I made for a month. That might seem drastic, but it was something I needed and the experience was not only a physical commitment, but also emotional and mental. I only did a month as I felt I was ready to get off of it when I couldn't stand the green juices lol. YUCK! haha. I lost about 25-30 pounds and got a lot of my strength back and after that point I did continue to loose, though struggled here and there. So, my zen experience, which is what I needed at the time, jump started me.
Anyhow, I barely exercised, in fact I think I could do like 3-5 minutes here and there. It wasn't a priority and I think in most cases exercise in the beginning isn't that high on the list, not until you have gotten down in your weight. Not saying that you shouldn't exercise, but the food and diet changes are more important in my opinion. My back during that time hurt so bad I would literally sit and cry at my desk while I tried to get some work done. It was so painful, upper back, and I read that is because I was just now starting to use my poor muscles again. The pain lasted for two weeks and I slowly started to build up my back muscles, but not by doing much, just being getting up and walking around mostly.
After my juice feast, that is when I started doing more and I still struggle with exercise to this day, but I can go for longer walks and longer periods of time with aerobics. I know I can and push myself, but starting out I just wanted to get me "moving" and that didn't take much. I would be exhausted after a 10 minute walk and have to puff and suffer on the way home.
One suggestion is to look at those portable bikes, not the big ones that cost a lot, I'm talking about the mini ones that are like $30 bucks. You can sit down anywhere and even use it for your arms if you choose to. You are not putting all of your weight on you or the bike, so you can pedal a bit here and there and I bet you could even add small weights to do your arms or heck just move your arms. It might be something you can do while you're in this moment, meaning not able to move a lot.
The other thing is to get up and do small bursts of walking. Not much, even a minute up and about can really benefit you. Don't push it right now, focus on the food and diet and slowly you'll start to see a difference. When your body is ready it will want more and then perhaps you could look into something like swimming or other types of exercise.
I personally would love swimming. I'm very tempted to try it.
Fell off the wagon...
And I've already been going through the recipes section and copying down some that look good to me! 
