small but annoying problems

[sodaking663rd]

first i have a 1993 gt hatch.
the left horn button fell off. any idea how i can re-attach?
also my side bolster adjuster wheel on the driver seat has also fallen off. any tricks to re-attach that?
i know i know my car's falling apart...one more thing...my driver-side headlight is unsecured on the side...i cannot figure which bolt is loose. can anyone help on any of these issues?
Thanks!

 

[5spd GT]

I know on the horn button mine fell out (one of the teeth were missing) so it wouldn't stay in all the time so I bought a new one from www.50resto.com and put it in...

It just pops in...