HTML code in posts

I am designing a site that will (ideally) include a set of new books (this is for an academic library), along with their covers and links to the online catalog and publisher’s website. The HTML is generally rather basic–a set of tables with a basic header.

I would like to incorporate this page (HTML) into the wordpress site I’m creating for the library. However, I am not sure how to insert HTML into my posts/site. Everytime I put in the HTML, it simply comes out with raw code rather than any tables (i.e., output). How can I then incorporate the HTML so that it is read as code and then as actual output? I am rather new at this, so I hope that my inquiry makes sense.