Displaying content in an iframe

I am a new WordPress user and also new to all things coding. I am trying to create a page in which link buttons surround a central frame. When the links are clicked link specific content displays in the central frame. I have figured out how to design the layout using <divs> and an <iframe> using just HTML and CSS. When testing the functionality using code written in Notepad++ and Chrome for a browser everything works. However, in WordPress, I cannot figure out how to call and execute the HTML code (primarily just text and images, nothing fancy) into the iframe.
My questions:
1. Can I store HTML files on the server and access them with a link tag, or is this just not possible?
2. Do I need to have the HTML stored in a PHP file somehow? And how would I access the PHP file?
3. How do I set up the links to get specified information to appear in the iframe?

Any suggestions would be greatly appreciated as I am flummoxed!
(DISCLOSURE: I looked up “flummoxed” for spelling.)