You set up a VPN through your router--- there is a LOT of info on the site here to do that.How do you access your cameras remotely?
I went with a simpler solution and used ZeroTier. It's not a true VPN, but allows me secure remote access. Others have debated the pros & cons of VPN vs ZeroTier P2P connections. You can read up on that and make your choice. Either way--- don't PAY for either one. (OpenVPN is free)
The other thing you do NOT want to do is use DDNS and open ports through your router directly into your BI machine. It may not be right away-- but BAD things will happen sooner or later. You can read about that in numerous threads here on the forum as well.