#1. Get your eating habits sorted out. Cleaning up your diet by removing all the empty calories (sodas and chips and such) would be a first good step. Many will start to reduce fat just by doing this.
#2. Conditioning is important. Get yourself more physically active, get outside and move around. I don't mean that you have to start running marathons, simply walking and house/yard work will be a good start. A conditioned body is a healthier body, and it will allow you to use food better and recover faster.
#3. Start a simple barbell workout. There is no better way to add muscle than with a progressive barbell workout. It doesn't have to be fancy or full of big name endorcements to be effective. There are many good recomendations here on MAB, just pick something that appeals to you and stick with it.