hello lele__2007
To be able to set any port forwarding rules your connection needs to get an IPv4 address. If your connection is set to use an IPv6 or IPv4 CGNAT address, you’ll have to call 0800 707 707 and request an IPv4 address.
You can set port forwarding rules but they will be always on or always off. Any change has to be done manually.
Unfortunately the Connect Box 3 doesn’t allow access from the internet. I use a QNAP NAS with Browser Station and a VPN Connection to access the Connect Box 3 while I’m not home. You will need something similar, to have access to the Connect Box 3, when you’re not home.