here’s how I set up my centipede tubs: layer one is about 2.5 inches thick, soil & clay and is compacted until extremely firm, this is the layer that retains humidity and also prevents excessive burying in some species
layer two is thin, coarse mulch, peat, bark chips, really anything that is of a large size and doesn’t break down easily. this layer gives the centipede some texture to walk on and also is just deep enough to bury in to hide
then add hides, bark is almost always the best option, they prefer nearly flat pieces that are bowed up slightly, so that it creates a thin cave for the centipede to hide in and also gives it the option to cling upside down from the bark, I also add in springtails as cleaners
new smells and locations are always frightening to centipedes, it may take them a week or so to acclimate