update existing ebook

I have a self-help book that I want to turn into an ebook that is interactive. Most of the work was done by someone on another gig site, but the design is not good. I think it will take 2-4 hours from my experience with inDesign (not expert level, but I have used it and understand the work involved). The first person did the heavy lifting (inserted the interactive spaces), I simply need a few updates. I don't want to pay for inDesign to do it myself since I will likely never use it again.