Anyone Know Anything About Health?

[Faith]

I'll admit, I'm 20, and i have a really bad diet. I'm 5'7'' and really underweight, and have a lot of aches and stuff from not exercising right. However, i know nothing about health type stuff. I would like to gain a healthy amount of weight, and exercise and stuff, but how to i do that healthy. I hate worrying about dying young all of the time...oh, and if it matters, I'm 5'7'' and about 110 pounds, male...I just need to get some sort of routine in there, but I'm not sure what