Help. Connect to socks proxy using authentication

[mbman88]

I need help finding a method to connect to socks proxy using username and password so that I can use a browser to connect to the web via this proxy.

The proxy is the VPN's socks5.

http://username: password@proxy-nl.privateinternetaccess.com:1080/
I doubt this will work since it is "http" and most likely wouldn't work for a socks5, but I don't fully understand everything and I don't think it's necessary at the moment to sit down for a few days to read about how all these protocols work in networking.

socks://usernameassword@proxy-nl.privateinternetaccess.com:1080/
This is what I presume it should look like.
However, I believe these addresses are only used for a command line system-wide setup. If this WORKS then I am okay with this method.
Otherwise, Firefox doesn't seem to allow authentication OR even a way to add a "plain address" (proxy-nl.privateinternetaccess.com).
Chrome just listens to the system-wide settings.

And please don't tell me that if I'm using a VPN that should be good enough. VPN's are obviously a method to hide your location info and so many sites across the web block VPNs. I need socks. But I'd prefer to use a trusted socks rather than the random and questionable ones you can find on the web for free or even pay for.

I won't be back too soon, so sorry if I can't answer any questions right away.