How do I make a move on a guy?

Ok so there is this cute guy at my gym and we do smile and say hi regularly at each other (I know that means nothing but it does make my day when I see him). Well I’m feeling confident so how do I make a move on him to get his Instagram or phone number. I don’t know if it will seem strange since we don’t know each other, I was thinking of trying to make small talk and assessing the vibe then going from there. Also would it be strange to just ask him out of the blue for his contact detail.
Any tips will be amazing.