I am in dire need of help

I am 14, 5 foot 9 inches, male, and just under 110 pounds. How do I gain weight. I don't want to gain fat, mainly muscle. Doc said I need to eat more and exercise more. I want to have a healthy transformation. My arms and legs are skinny but I want to gain muscle in all areas evenly. Can someone recommend me which at-home exercises are good for me to try which can give me a good boost. I can try to commit 1hr a day to exercise atleast.