How to install a VPN on a home router?

I’ve read many guides and watched YouTube videos but still have absolutely no idea how to make it work. I want to use my VPN to watch blacked out sports and stream from other country’s but on my fire stick or smart tv.

I’ve had 2 VPNs and I believe they have instructions on how to install on a router on their websites. I’ve never tried to do it because some things don’t work well or at all with a VPN so to have it on all the time via the router might get frustrating. The fire stick might have your VPN’s app and you can run it from there. I watch blocked content by mirroring my phone or computer to my TV with the VPN on the device that’s broadcasting.