You can execute arbitrary elisp code from a link:
Clicking on the link runs the code and you get a greeting in the echo area.
All you have to do is figure out what code to run. The first step is to find out the keybinding of C-h f, so do C-h c C-h f RET and you see that C-h f is bound to the command describe-...
I found it easier to build Emacs from source: you get not only full Emacs documentation but also a more recent version, presently 27.1 instead of 26.3 (in Ubuntu 20.10).
Configure is straightforward because all the dependencies can be obtianed with: sudo apt-get build-dep emacs.
Add to $INFOPATH: /usr/local/share/info /usr/share/info/emacs /usr/share/info.