Time till eggs is very variable if even you get any eggs, remember because they lock even if you see the female build this still does not guarantee eggs.
The only sure things as far as timeline goes is to start the countdown when you witness an ovulation, after that it's 45 days (average till eggs)
Ovy
Pre-lay shed 14 days after ovy
Eggs 45 days after ovy
As far as signs there are many to look for here is something that might be helpful to you http://www.ballpython.ca/gallery/breeding.html, just remember this as a guideline you may or may not witness all those signs.