Looks like it's time for you to check out the "book" tag! :D
PDF or ebook is usually the preferred method for most folks to read novels, and PDFs are best for comics.
Make one page for the project and upload both languages to the page and then mark both "english" and "spanish" in the meta data for language and name the file accordingly and you're good to go.
Good luck! Don't forget: lurking on Itchio will teach you a lot so DEF read other people's books in prep for the jam! It'll be very informative. :)