The whole ectomorph thing I think is mainly a myth, so dont get too hung up on what your body is naturally like.
I used to be thin and skinny, now I am big and chubby. Your size is ultimately determined by how much you eat (calories in) and how much you exercise (calories out). Weight exercises are of course going to be best for bulking up, but not essential if you like something like swimming or sprinting.
I am also 6"2 and was 77kg about 4 years ago, it's a good running weight
When I got to about 85kg I stopped looking skinny, so good target to aim for.
Have you read the bulkers corner thread?