You have two choices! 

1- install Greasemonkey on Firefox. Or Tampermonkey on chrome
** (open the extension page on your browser and drag and drop) **
* Then open the extension page on your browser and drag and drop each of the scripts and install. 

2- install Adgaurd on your computer (a really good software)!  
. . Go to settings then Extensions,. And drag and drop the scripts and install one by one . . 

** (https://piratebayproxy.live/torrent/15860391/Adguard_Premium_6.1.258.1302___Patch) **

(if using Adgaurd you don't need Greasemonkey on Firefox. Or Tampermonkey on chrome, Adgaurd will automatically run them on your browser, if it supports extensions) 


* you can grab even more scripts on 
https://greasyfork.org/en/scripts?page=1&sort=ratings 
** (right click on "install this scrip). And "save link as") **


* Scipts list: 

500pxcom Download Photo.user.js
Absolute Enable Right Click  Copy.user.js
Add Spotify to YouTube.user.js
adfly  lienscashcom  adfocus  bcvc  shst bypasser.user.js
AdsBypasser.user.js
Allow Copy and Context Menu Continued.user.js
Anti-Adblock Killer - Reek.user.js
Auto Close YouTube Ads.user.js
Bypass Wait, Code,  Login For Chrome.user.js
Bypass YouTube age verification.user.js
Capture current page.user.js
Center Image.user.js
Crack Url Wait Code Login.user.js
CRX Downloader.user.js
Dark Tube.user.js
Debrid Download Helper.user.js
Depositfiles Download.user.js
Direct links out.user.js
Directory List - Folders.bat
Disable audiovideo autoplay.user.js
Don't track me Google.user.js
Download YouTube Captions.user.js
Download YouTube Videos as MP4.user.js
DownloadAllContent.user.js
DuckDuckMenu (1).user.js
Enable Right Click - Reek.user.js
Enhanced word highlight.user.js
Error Page Auto Refresh.user.js
File Hosting Download Manager Disabler.user.js
Filehippo - Replace Download Manager with Direct Links.user.js
filelisting.txt
FYTE Fast YouTube Embedded Player.user.js
GBookDown - Download Google Books.user.js
Google Book Downloader FoxySpeed.user.js
Google Drive Direct Links.user.js
**more**


Cheers