I've created an empty folder in the root of the Kindle's directory called USE_ALT_FONTS
And another folder named fonts in which I copied and pasted the four ttf files of the font into:
Fontname Bold Italic.ttf
Fontname Bold.ttf
Fontname Italic.ttf
Fontname.ttf
I ejected my Kindle and did a restart. When I tap the "Aa" button I can see the font I installed with a bunch of other fonts
Plus, I can't see the italic/bold/bold italic version of the font.
Edit: I saw this picture online and these are exactly the fonts that automatically appeared on my Kindle.