I guess if I had older dcks during the day I might do things a little differently but at the moment, mine are 2 and under. I let them just play with whatever and wherever they prefer. I have no restrictions for their exploration except concerns for safety or if they haphazardly start dumping buckets. And for some reason that's what they started doing just last week.
So I'm teaching them the idea they need to pick up 1 bucket before they go onto something else.
I have a 4 yo and 5 yo that come at 3:00 and they're by far the worst. Well, the 5 yo is great at picking up. But the 4 yo seems to be 'out there' sometimes(you can tell him something 10x and he still gives you a blank look) and will let everyone else pick up for him. But it's the busiest part of my day so it's spent rushing them through snack, bathroom and getting everyone outside.
Very seldom have I created 'centers' for dcks to play in. I like to watch what they can do with multiple types of materials. But I always encourage them to help in clean-up.