How do u make it so u can actually read the pop up menu in the thunderstro theme he said install the font but i dont know how and theres no read me.

put the font into your windows\font dir

the font should have been included with the theme, you just need to copy it into your font folder

the font should be included with the theme and located in your $themedir$misc folder. Just copy it to windows\fonts and recycle

is it true that u can install font via this theme.ini?
if yes - is it limited to ttf or could i as well install a Type1 font which consists of two files?

I thinks there's a module around which automatically installs fonts. Look around on loose-screws or smt.

Install the font by theme.ini file.

[Install]
Font="misc\Silkscreen.ttf"
FontName="Silkscreen (TrueType)"
Trying this way does not always work tho.
Mixed results, maybe my config...

You can temporarily install the font in mem with lsfonts.
Add these lines in your theme

*NetLoadModule lsfonts-0.1
*LoadFont "$ThemeDir$Misc\silkscreen.ttf"

Again there is issues with some modules
that dont like it this way. Rainmeter for one.

I suggest copying to your windows\fonts dir.
This is the best way to do it.