Well, since your pup is just over ten weeks old, I am glad you are using positive techniques and not yanking and cranking.
Play with your puppy. Play, play, play with your puppy. It's a baby. Nothing wrong with making a game of some obedience, but keep it light and fun. Talk to your puppy. When you see your puppy laying down, tell him, Good Down. As for the stand, I think it makes more sense to teach your dog to pay attention to your face, with a look or watch command, using treats. And when the dog makes eye contact, give the treat. Then start building some length to that. Slowly, and not just longer and longer, but this time, give it to the pup immediately, the next time wait three seconds, then give immediately, then wait 4 seconds, then wait two seconds. Build the attention span, and when you give it to him, always say, "OK, good WATCH (or LOOK)." What you are doing is teaching the release word, OK, as well as building that attention.
When you start teaching other commands, lots of people like the dog to maintain a position until released without a STAY command added. You told the dog to SIT. It should SIT until you tell him to do something else, or until you release him. Others use SIT and add STAY, and give an OK if the dog is to be released from the STAY command. What is important is consistency. Whichever. But if you teach the dog to maintain a position until released with an OK, then when you manage the STAND position, you can then use the attention command, LOOK, or WATCH to keep him standing and paying attention to you, like if the vet/groomer is going over him -- only practical reason for the STAND command. But the LOOK or WATCH, can be given to the pup when you think the pup is about to break the position, and it can give you a little more time (usually to give your release word, before you would otherwise have to correct).
But yours is a baby now. The idea of yank and crank with such a baby makes me cringe. I know you aren't but, it suggests you are concerned about getting these obedience/Rally moves down properly and at this age, it is asking a lot. Build the relationship now. He's a baby. Keep it fun.
Bear Cub, Hepsi-Pepsi
Cujo2, Karma Chameleon
Ramona the Pest, Kojak -- who loves you baby?
Tiny Tinnie, Susie's Uzzi, Kaiah -- The Baby Monster.