Simple solution for you; Push ups. I've had more gains doing push ups than going to the gym actually
Push ups are a compound movement and work all kinds of muscles. Push ups is also the best chest exercise out there either with a machine or without
...you will have amazing gains of weight, power and looks in your first 30 days if you follow this pushup routine. Best way to start is 10 sets a day of 5, 10, 15, or whatever your max is, you go a bit under. When my max was around 75 I'd do 10 sets of 50 for a total of 500 push ups a day. And do it whenever there is dead time in the day
When I wake up, I bang out a set of 30 or 50 to get my blood flowing... it's like an instant coffee! Waiting for food to warm up in the microwave, waiting for the metro, waiting for my computer to start, waiting for the light to go green on a busy sidewalk...it's all dead time that you will loose if you don't use it, so I try to get a set in there...bonus points the more people stare at me I like that!!
Nutrition for weight ...dont obsess about it, just follow simple guidelines:
-Eat one gram of protein per pound of bodyweight a day for your muscles
-Add fat and carbs for calories
- when you eat carbs, try to eat your carbs right before and after workouts to have as much carbs converted into muscle, otherwise it will be converted into fat
-Greek yogourt before bed --- slow digesting casein protein drip feeds protein to your body through the night while your body is rebuilding itself... you will feel a good deal better the next morning!
-Creatine supplements are cheap... adds 10 pounds of water and a bit of muscle to your frame!
Also if youre skinny with a fast metabolism, you can't just eat more and do nothing, otherwise it will pass straight through your body and out, your body won't have a reason use that food for new cells. You need to put in the work with the pushups for the food to have somewhere to go to
good luck!