Start with a calorie deficit, eat low calorie high protein meals to keep you full. Half of working out is diet. The other half is just showing up at the gym to start. Warm up with cardio, lift weights, use the machines, figure out a gym split. I personally do upper body rest lower body lower upper. It’s hard to get started but once you start showing up to the gym you’ll learn as you go! Also drink lots and lots of water