Looking to GAIN WEIGHT - workout advice

Good day FB community

I'm a 21 year old male, looking to actually gain weight, I have been underweight for some time. I'm 63kg and 1.82m in height

I'm wondering if anybody has any suggestions as to which videos would aid the most in helping me to pick up weight in muscle. Also (funny enough) I have a little belly fat, so are there any specific videos anybody has found that are really good at trimming that region.

Thanks for any and all suggestions, it is greatly appreciated