You do not actually load fonts into Titler. You install them on your system, and if they are fonts that Titler (also PS, AI, InDesign and others) can use, they show up in the font list in Titler.
Good luck, and hope that helps,
When installing fonts into the system, it might be useful to keep this ARTICLE in the back of your mind, if you experience any crashes in Titler (or odd behavior in PS, AI, etc.).
If these are well-written fonts, from a reputable source foundry, there should be few, if any problems with them. Keep a note, however, of the fonts that you have installed, in case you later experience problems. That will make troubleshooting much, much easier, as you will then be dealing with a much smaller sub-set of fonts.
Also, some fonts, that do not cause crashes, will just not display in Titler, or some other Adobe apps. The only workaround there is to choose another font, or find a better-written version of the problem font.