Can not download videos anymore Please Help

I used to have a way to download vidoes off of Youtube with firefox. See I download tutorials for blender so I have them no matter what. But now Firefox has updated and I dont understand how to do it anymore. I tried buying the pro downloader but i could not make heads or tails of that. Does anyone have a current method of downloading youtube videos ?
Not necessarily Firefox but any browser that is capable. I did search the web I just feel overwhelmed by all the solutions I
Hopefully someone knows a tried method…

keepvid. Either copy and past the URL to their site, or install the bookmark bar addon. Will let you download up to 720p for free

Been using this for a year now, works great, downloaded lots of videos from YT, and works on other sites.
Set “intensity” to “safe 1 thread”…and turn off “Show Achievement Notifications”.
Updates often(keeps up with YT changes)
Stay away from DVD video soft…its a joke!

Hey Thank you Guys.