The hardest part about bulking is eating clean while increasing calories. I think increasing calories is really tough unless you know exactly what you'll be eating everyday and know how to make it. This is essentially what you need to do. When bulking I usually try to get 4000 calories everyday. It takes some time at first for your appetite to build up, but it will eventually (usually within a week for me). How many calories really depends on a lot on how many you burn. You definitely need to burn more than you intake. They say for every 1500 calories you burn, you lose 1 pound. And of course the other way around applies too. You have to take into account the amount of calories you naturally burn, and the calories you burn by lifting and running and whatever else you do.
It was really hard for me to establish a diet, but once you do, bulking and cutting become a lot easier. If you know exactly what you're going to eat tomorrow at every meal and you decide to bulk, all you have to do is increase your intake of whatever it is at every meal. There is something about oatmeal I really like, I feel like this is something that can go a long way to helping you bulk up. I always have it in the morning for breakfast mixed with a scoop of whey. When I'm bulking I blen oatmeal into my protein shake (this essentially makes a weight gainer, but probably more healthy and better tasting). Oatmeal of course is also incredibly cheap.
The good news for you is that when you do start really building muscle and putting on weight, it seems that being lean won't be as tough for you. Good luck!
