NAT configuration on Dedicated server Ionos host

[fajja]

For the last couple of weeks I have been reading and learning how to set up Proxmox and VM's. For the life of me though I can't get NAT IP masquerading set up, every time I do the server is unreachable. I'm probably at the point where I've read the same documents so many times I'm missing a simple step! It is just a small dedicated server that I'm using to practise on but once I master this then I'll set up my projects on a bigger server, each VM will need access to the internet. For ease of not confusing me i'm going to tag the various IP's as A B C etc

auto lo iface lo inet loopback auto eno1 #real IP address iface eno1 inet static address [B] IP*A*[/B]/24 gateway [B]IP*B*[/B] auto vmbr0 #private sub network iface vmbr0 inet static address [B]IP*C*[/B]/24 bridge-ports none bridge-stp off bridge-fd 0 post-up echo 1 > /proc/sys/net/ipv4/ip_forward post-up iptables -t nat -A POSTROUTING -s '[B]IP*D*[/B]/24' -o eno1 -j MASQUERADE post-down iptables -t nat -D POSTROUTING -s '[B]IP*D*[/B]/24' -o eno1 -j MASQUERADE

In my hosting control panel I have set up a virtual private network:
subnet address = IP*E*
Subnet mask = IP*F*
IP Gateway IP*G*
Should these IP's appear in the coded section above? I'm pretty sure I have now tried all variations to no avail. For example should IP*D* be the same as IP*G*?
Should IP*A* be the same as the IP I use to connect to the server?

Apologies for the complicated question for what is probably a simple answer, I've been throguh everyone so much my brain is frazzled! I do love the feel of ProxMox though so if I can get this to work I will be sticking with it.

Ionos states that VM's must be connected through NAT rather than a bridge so I can't use the other methods.

Thank you for your help!

 

[fajja]

5: vmbr1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 36:93:7d:4d:44:0b brd ff:ff:ff:ff:ff:ff
    inet 10.10.10.1/24 scope global vmbr1
       valid_lft forever preferred_lft forever

I get this error when following the docs and using any variation of the IP's or making up random ones. I assume once the "no carrier" message goes away its safe to restart the networking