Formatting pages that read right to left

Hello,

I receive indd files from Japan very often and their page formatting is to read right to left. Whenever they give me the files it's already set up and it's very handy when exporting to pdf or preparing to print. However for the life of me I haven't been able to figure out how they set it up to begin with if I were to ever need to create a document from scratch.

Whenever a new page is added it appropriately adds it to the left of the last image and so forth, and if I were to need to export this to the PDF the PDF knows the formatting and appropriately arranges them of which one comes first.

How would I go about setting this up from scratch?

Thanks