You wanna gain weight, then weight training is important.....should be your primary focus
As for the other stuff pick a sport and build a portion of your training around that .....whether its hooping, boxing, ball, soccer, hockey whatever the fukk.....
Also try not to gain weight too fast, so you actually have time to adapt to the changes ......
Diet........... figure out your macros and put yourself in 5-10percent surplus
Ratio should be something like
50/40/10 or some shyt ....
Lots of carbs and protein, low fat .....with dieting its really about caloric needs and not the method itself imo.....you can even do some Atkins shyt, where if you eat enough you still end up gaining weight.....
