Simply use an extension like tampermonkey or violentmonkey or whatever monkey you like and install whichever userscript you want :)
Firefox and Chrome with Tampermonkey or Violentmonkey.
If you want, you can also check out my Greasyfork Profile, that's where I usually update my userscripts first:
https://greasyfork.org/en/users/187317-funkyjustin
Sometimes I won't be able to update my userscripts to my GitHub since I prioritize my GreasyFork page so here's the direct links to my userscripts over at GreasyFork