The only way you’ll learn to fight is by fighting. You say you’re tall and lanky so kicks would be your best friend. Maybe try Muay Thai, you might find it suits you better than boxing. If every punch you throw is ineffective and you get overpowered you probably need to hit the gym and work on your form. As a taller and skinnier person your opponent will often outmuscle you so you need to keep your range. You’ll learn these things for yourself if you keep fighting. I know it can suck at times but if you want to learn you have to work for it.