coop housing

i have just got 3 chicks, they are in there new coop but i am not sure what to use in the housing area, sand or sawdust, any advice please

What sort of coop is it?

If it is one that has a pull out tray under the perches then newspaper works for me with a sprinkle of BioDri.

When it needs changing just role and fold it up.

I'm a huge fan of Hemcore. It's the best I've found for the coop floor, and so soft I use it in the nest boxes too.
Really absorbent, so makes the daily poo pick a doddle, so the coop stays fresh and clean a lot longer.  Not easy to source though. I get mine on line and get 2 bales at a time to make the £5 delivery worthwhile.