Brand New To All This. Gaining Weight not Loosing

I'm new to dieting, however I'm dieting to gain weight not to loose it. I just want to say hello to everyone.

I'm John. I've been underweight all my life and premature when I was born. I recently have had some health issues due to being underweight.

Any tips for gaining would be greatly appreciated.

I currently workout 3 days a week for about 30 minutes a day. In a month that will increase significantly. Right now i'm targeting 3,000 calories a day next week I would move up 500 calories and so on until I hit around 5,000 a day.