Here's an idea. Go to bed as soon as you finish reading this post. Wake up at 4:30 AM sharp. Fill up a water bottle as needed. Do as many pushups as you can. Do as many squats below parallel as you can. Plank for as long as you can. Do as many burpees as you can. If you don't know what any of these terms are, look them up and make sure you do them properly. If you're overweight, go for a run, or at least a jog. Get a shower, and a proper meal with protein. No processed shit. Take vitamin C, D3, and Zinc. Look into other supplements as well. Do this every morning until you can do at least 20, preferably 30 pushups easily. Proper form. Chest touches the ground each time. You will start to get a clue. Get a gym membership. Now start doing bench presses, leg presses, squats with actual weights, deadlifts, pullups, chinups, lateral pulldowns, calf raises. Look up something like "starting strength" for guidance on gym routines. Do as many workouts outdoors as you can as well. It's summer. Good luck.