New hamster

Hello! So we just got a new hamster on Saturday. He's a Russian dwarf. We've got a great cage set up for him with a bedding area down below and toys/food up top. I've never had one before, so I'm wondering if anyone can tell me how long it takes for a hamster to feel comfy in his new environment? In the two days we've had him, we've only seen him come out of his nest for food and water then he quickly scurries back down. Also any general hamster advice for a newbie?