That is correct. Using Open VPN, you log into the VPN running on the router and you are now on your home network.
------------------------------------------
My general VPN post
There are two types of VPN, do not get them confused.
The type depends on where the traffic conversation originates
1) origination: local home network, destination the internet.
This type of VPN purpose to hides your activity from the internet, it is outbound, it normally costs a monthly fee to use. Direction is from your home PC to the internet, going to your bank, google, porn sites,,,, this not what you want
2) Origination: the internet world wide web, destination: your home network
This VPN type is used to provide a secure connection onto your local network, in bound to you local home network, from your office computer, your cell phone in your car, tablet at the coffee shop.. This is what you want, it does not have a monthly fee and is normally completely free. OpenVPN is this type of VPN.
If you home internet provider is a cellular network, then
DDNS (dynamic Domain Name System) may not work, the DDNS is needed for most Inbound VPN services (OpenVpn), so OpenVPN may not work for you.