how can a skinny guy put on muscle?!

Take whey protein and take it before and after workout
Take Casein protein or Whey protein mixed with milk before u sleep

Plus make sure u lift weights (preferably free weights) in correct posture and form,
If u have passed growing stage u should try deadlifts, benchpress and etc..
For muscle gain do 4-6 reps of 90 % max weight along, around 3-4 sets + warmup sets,
don't overdo; do i major and minor muscle group; take half-day rest and sleep well; overtraining is waste of time, effort and will cut away all ur benefits...
dont take weight gainers, they r stuffed with rice anyway....just eat lot more and drifnk more water...

I don't recommend steriods (long term problems) , If u become so desperate, id recommend letrozole (femara) after consulation with doctor on end of every cycle..

If u passed growing stage try gymnastics, parkour, martial arts etc<--- these could otherwise cause stunted growth if done improperly.... play cardio like soccer, swimming etc....have fun

Not all of us r born to b hunks by genes, there are so many hunks around that it doesn;t mak ppl stand-out anymore much, try increasing ur intellect <--maybe ur gifted there ...don't neglect work/study and give priority to work+study+career, u wouldn't wanna end up as a frat hobo hunkie-doodle than a successful skinny guy... ; and ur lucky that u r not obese; obesity could lead to more problems...

Hope this helps, best of luck,
It would be nice if i got som feedback

Lift free weights and eat more.