how many threads are there about gaining weight, can't you just search and read all the info you need has been posted before
High carbs and protein diet + training. If your not too concent on bodybuilding, basically eat whatever you want, but with the extra carbs; bread, pasta, rice etc, prot; chicken, steak, TUNA etc
Just eat loads, if you think your eating enough you most likely ain't so eat more. CARBS!!!!!!!!! BREAD PASTA RICE EAT