Hi, and welcome to the Forum!! That's a very pretty leopard tortoise, and the design on the carapace is a bit unusual. It will be interesting to see how it changes as the tortoise grows.
For substrate, I like to use something a bit smaller (chunk-wise) so its easier for them to walk on. My substrate of choice is the fine-grade orchid bark. But quite a few folk on this forum use coconut coir.
What a pretty creature,never seen one like that before , & showing her high class , Yvonne suggests orchid bark , crikey & I never knew orchids even had bark .