So nice that you have a puppy!! Don't forget to post some pics..!!
About "sit": I learned Tillo to sit, but at the training they know we also show. So with obedience Tillo doesn't have to sit without me telling him to sit when I stand still. I learned Tillo the command 'stand', so he knows I can tell him more things when I stop walking: sit, stand, down etc.. This makes him wait for the command (most of the time :D).
Tillo also has to sit before we leave the house, eat, cross the street etc, but for example when he sits without my command I ask him to stand.. (can you still follow me.. :rolleyes:)
I do think it is important to learn the pup to 'stand' when you go to puppy training. Most of the trainings are very focused on the 'sit' and when you wait to long it can be harder to make them stand. When they see you have a treat, they will sit automatically..
You can also learn 'sit' on one leash and stand on another (show) leash. This is not my choice, because I like to let Tillo sit in the ring when it's not his turn.. otherwise he becomes very impatient…
One other thing with training is you learn the pup to look at you when walking on leash. In the ring it is nice to have a dog that looks strait ahead. I do change leads for this. One leash is look up, show leash is don't look up.. (I don't look at him either)