We did puppy classes as soon as our mini poodle x had her 2nd vaccines. We did learn some things there, but I feel we learnt more from books and you tube, as maybe the trainer just wasn't great. Great for socilisation though if nothing else.
We started with a praise word- ours is YES, and helped reinforce good behaviour. Sit was fairly easy by having a treat in your hand, lifting it above the head till she sat.
Ours rings a bell to go out for the toilet and will do anything for a ball. She retrieves it, then rolls it to your foot to pick it up and throw again. The 1 thing we didn't teach was to open the electric car windows with her paw- which she loves doing to stick her head out!