How can I gain visible muscle? (SliceAndDice_)

Hello, I'm currently 17 as of 15th October 2017 (Now 21st November 2017) and I want to gain visible muscle. However, I'm around 6 foot 1'/2' and weigh 140 lbs. I look very skinny and quite bony (I can fit my fingers around my wrist and have a lot of room)..