First of all, what is your diet like? Are you getting a well rounded diet with fruits, vegetables, and lots of protein rich lean meat? If not your body will never grow regardless of what exercises you do. If you are eating all those things, remember that you'll need to eat more if you want your body to use the calories for building muscle and not just surviving.
If you want to get big and don't want to go to the gym and don't own weights then you should go work on a farm. Bail hay, lift horse feed, and pull stumps out of the ground. I don't mean literally, of course, but you need to find exercises like those to perform. They all have a couple things in common:
- They are all full body exercises
- They vary a considerable amount from
- They are probably not something your
body is use to doing
Since not every body has access to a farm, some good substitute exercises would be:
- Bench press
- Some sort of row
While teaching you how to do each of those exercises is somewhat out of the scope of this answer, I encourage you to read up on each and learn to do them safely. Many exercises like them can be down with very little to no weight. You can also almost always substitute a real world item for the dumbbell/barbell.