You don't need to connect to the VPN when your at home. It's only for when you are on a different network. Be it the WiFi at your work, airport, Starbucks, strip club whatever. It will also work over your cell plan. No need to actually be connected to WiFi.
You'll need to have every device (that you want to be able to access your network. For example, cell phones, tablets or laptops) get a certificate that's generated by the VPN server to access the VPN. Any device that is already on your Lan 100% of the time (desktop, NVR, whatever) won't need to do anything related to the VPN. Generally it's a good idea to create a different certificate (with different PW) for each device so that if it becomes compromised, you revoke that certificates ability to connect.
I would definitely advise against giving guests access to your VPN. Two reasons, 1) since they're at your house, they won't need to VPN in. Just give them your wifi password and let them connect. Or give them your guest wifi pw if you have a guest network set up.
2) once your guests leave your house, if they're still connected to the VPN they can access your local network. There's no need for that since there guests and it can creates a security issue if they lose their phone.