If you use
FBReader 0.8.4 the font should show up under Settings (tools icon) -> Styles. Unfortunately the font is a global choice, so you may need to reselect it if you switch back to an English document. Even better will be
FBReader 0.10.0 (or 0.10.2), once it is available again. Note that FBReader 0.8.14 won't work, because it has the font hardwired.
If the font does not show up in the list in FBReader 0.8.4, then it is probably not installed correctly. Your description of the softlink does not sound right, but the actual link you made may be ok.