best way to move site to a wordpress install

Depends on how well organized your current content is and how well its current structure matches the structure of your WordPress pages…

the site format it’s basically the same

here’s the site https://www.pctechtips.org

and here’s the wordpress install: https://www.pctechtips.org/wordpress

thanks

Are the existing site’s postings stored in a database?

no, not in database