Convert Word files to HTML (ePub) Json format

We are creating an Ebook app. I have large files in word format (and in excel format) however the programmer wants the files to be put out in a very specific way. They want the file converted to epub which is HTML in a Json format. (I don't know exactly what that means). I will attach the word file and the way the programmer wants the file. Best if you could create a tool to do this automatically, or you do it yourself. I have very large files with hundreds of large lessons. I hire hourly but you must let me know how many hours it takes to convert all the files (I will assume that you have a way to do this automatically). Whoever will be hired will also chat with the programmer to make sure that they know what the programmer wants.