Hi @Connor_Johnson1, I am Leandro the creator of the Pack, more than happy to help!
The CreateCustomer action does indeed return the entire customer object which has the id on it. One thing you can do is store the customer when created and then read the id from it, the following way:
I am using the ParseJSON because Coda does not the type of thing that you store in the Result column, but maybe @Scott_Collier-Weir knows a better way.