no for reals tubby ignore everything and listen to me for a moment. the first step is building your muscle and taking care of your joints (so you can do real cardio). fixing nutrition too but let's just focus on what you can do to impress yourself and everyone else right now.

big boys are big boys there is no changing that about you fucking embrace it. understand that every time you life you build muscle that consumes calories. building muscle to consume calories is how the big guys get cut. you first get yourself swol, learn to eat, and then work on your joints/tendons (stretch, this will hurt, you will do this and love it).

look at all the big boys with big arms that's your starting phase. after you've taken 10's of pounds if not way more of weight off you will literally be lighter and stronger. go lift 40 pounds of something right fucking now and know that's on your body.

resistance training and weight lifting with 2x-5x brisk walking a day (to a sweat) will fucking transform you in a matter of months. then a year. and in 2 years you will be a new man.