Symbols don't display in text

Hi all,

I'm working on some of my first assignments for TAFE and need to add some symbols, but when I open the in line text editor and click the symbol dropdown (@) I can add the ones on that menu but when I choose one from the "other" option, the symbol doesn't show. I just get a square. I've tried using the unicode but it doesn't want to play ball either. Is there maybe some kind of library folder I've not installed or downloaded from somewhere?

As you can tell I'm quite a new user.

Thanks!

Red_Hotter