Did I mess up my bioactive vivarium?

[Mambaconda]

I was building my new bioactive vivarium and was pouring in the soil when I realized I didn't have enough. I put my 2 cultures of isopods in to get them going and went to get more soil. I came back and added the rest of the soil (still crossing my fingers I didn't buy bad soil) and finished building it. It's been 3 days and I still don't see any isopods and I'm worried I crushed them with the second layer of soil. I did leave the carrot slices in that came with the cultures so maybe they are finishing off the carrots. Should I have added them on top of the soil or will they start showing up after a while?