Advice anyone? Information on multiple pages or all on one page? (SquareSpace)

Hi, I had a website that features information on around 20 different subject matters (all related to writing). Each subject had its own page. For various reasons I wanted to transfer this information to a SquareSpace site that I already own. However, the template does not allow for a lot of pages (not nested within one folder anyway) and I ended up putting all my information on one long page (divided into h2 sections, with internal links). Will that impact SEO or make no difference? Should I look for a different template that allows me to break this information up again? Thanks in advance.