Progress? Tips please!

Kiddo is 3.5 years old. We're on day 2 of potty training. I understand it is still very early. He refuses to be naked so we've been doing underwear only. He sat on the potty plenty yesterday, but only for about 10 seconds at a time, nothing in the toilet. Had about 3 accidents, but seemed a little unphased. Today he said "pee goes on the floor" but not sure if he's just asserting some control. Do I just stay the course, let him keep going in underwear, and hope eventually he will connect the dots? I know it's still only day 2 but would like to work our way up to being able to leave the house eventually.