Re: backticks doesn’t work, term is not intuitive to forum users
A backtick is not an apostrophe or single quote, it’s the key that normally has a tilde in it as well. Check this picture, it’s the upper left key, in red. That’s a backtick and it’s different than a normal single quote or apostrophe.
For the terminology regarding HTML, you can easily add additional instructions for your users. The files you need to modify are in your template directory and called edit-form.php and post-form.php. You can link to a popup with additional instructions (which you would need to create for your users), or just add more verbose instructions there. It’s your forum: you can do whatever you want.
Also, even if your users don’t get it, they can still post. Things that look like links become links automatically, and the post will still be useful without italics and bold.
But, for backticks, you’re using the wrong key. It’s not the quote key, look on the upper left by the ESC key (on a US keyboard anyway.)