My baby, Siu Pao is 15 weeks old..he knows sit, stay, down although he doesn't like to do down and I never insist it so the down is kinda inconsistent
He will forget all the above commands when we are outside though
He also knows go sleep means time to go in to his crate and sleep. He will sit beside my bed to wait for me to bring his crate in from the living room. He knows let's go for a walk. He knows it when i say "where is the bully stick?" because he will always hide it and when I say that, he will go fetch it
I didn't train him in particular as he is smart. I just say the word whatever he is doing and he is catching it fast.