To create a new soundpack, replace the GB_PACK string in language.txt with your soundpack's name, then replace the sndinfo definitions with your own sounds, for example:
In sndinfo.txt, add
gearbox/pack/tick sounds/[soundpack name]_tick.ogg
gearbox/pack/open sounds/[soundpack name]_open.ogg
gearbox/pack/close sounds/[soundpack name]_close.ogg
gearbox/pack/nope sounds/[soundpack name]_nope.ogg
(replace [soundpack name] with your own name!)
And you're done! Just select "Custom Soundpack" in the Gearbox UI options, and check if your sounds work.