InDesign from Adobe Express

Hi due to computer problems where I had to send my computer that has capability to run InDesign to the tech store for repair, I had to upload my InDesign file to Adobe Express to keep working on it.

Now I have my Windows PC back, I want to upload the Adobe Express design back into InDesign to keep working on it. My google search says to upload it as a PDF which makes me concerned since it isn't a design format, will it interfere with the quality of the design? Would it be better to keep working in Adobe Express to finish the book?

I really want it in InDesign to use ruler guides as in the attached screenshot to ensure everything is lined up exactly right. Eg, I want the headings on each page to be in exactly the same place on each page. With Adobe Express, I've had to hold a ruler against my screen which feels really imprecise. 

I hope you can help. I always try to self-resolve with Google/Adobe online info first but I really appreciate your real-life experience.