If your pup doesn't respond to the SIT command, then you'll have to work on that first. You'll find it really hard to teach him not to jump if he can't sit.
Keep practicing over and over till he learns. Reward him everytime with treats and pats. Whenever you teach/train him, Have treats in your pocket, that way it's easy to reward him everytime he does something you want him to. Have you been teaching him to sit? If so, how? Has he been desexed?