It can anywhere between 1 week to say 1 month 'till you see eggs. Usually though, there is nothing to it, you put a male and a female in and they will breed. Some signs can be, lots of digging activity, the parents not really leaving thier cave/hole/pot/whatever, the parents trying to attack you if you get the close to thier cave/pot/hole/ect ect. When the female has an orange belly it generally means that she is ready to breed, I can't put an exact number on it, but say 2 weeks after her belly is orange you will see babies (2 weeks is to give her time to lay the eggs, then for the eggs to hatch). Hope that helps.