Help with subnet

You want to have a private subnet or what? Just leave everything blank then and define the addresses inside the virtual machines that take part in that bridge.
Or do you want to have a subnet mask? That's to be configured in the CIDR notation.
 
You want to have a private subnet or what? Just leave everything blank then and define the addresses inside the virtual machines that take part in that bridge.
Or do you want to have a subnet mask? That's to be configured in the CIDR notation.
How can I define it inside of the Virtual Machine sorry I'm new to proxmox
 
I guess that you don't have Proxmox inside the virtual machine, so this isn't really a Proxmox issue.
How to define a network depends on the OS that your VM is running on. Under Debian for example you would edit /etc/network/interfaces.
 
We have it on our dedicated server, as me and my mate are splitting it but he wants his subnet linked up and we are using Ubuntu 18, how would I do it the other way?
 
I have not the slightest idea what you are trying to achieve, sorry. If your mate knows what he wants, why don't you ask him, how to do it?
Ubuntu uses netplan or NetworkManager to define networks, so that's where you should start.