Dude, if you want I can tell what I am doing. You can do it all at home with resistance bands, two liter drink bottles, gallon jugs, and body weight, at least for the time being. Eventually you will need to get proper weights or go to a gym. I will have go myself before much longer.
It takes an hour every other day. And as
@NickyA said you may be technically at a healthy body weight but your body fat percentage may be a bit high.
You will still need to eat a descent amount of calories and focus on protein. The biggest difference from me and you is you will need to avoid carbs, at least for now. Where as I am needing carbs, plus plenty of protein to gain. I have already gained 13ish pounds in a month. Obviously some of it was fat due to how much I am having to eat to gain muscle. However, I am still wearing the same size jeans, so I must be doing ok on the muscle side, and the fat gain is not really noticeable. My jeans are however tighter in my quads and my glutes, the muscles feel tighter as well. My shirts are tighter in my chest, arms, and shoulders. I can 100% tell I am stronger and starting to look bigger. My goal is to just gain 10 pounds and see how I feel about it. I already passed my first goal. At 6 foot I am assuming I will want to settle around 170ish to 190ish, but not sure exactly where I am will be happiest, healthiest, and look the best. Because a 6 foot 180 pound man, that is mostly muscle is a big strong dude. Probably taller, bigger, and stronger than 80% of men.
So just start working out. If you want any information just ask.
