@bholmes12 I'll try to answer these as best I can from memory:
1) Before you deploy the vMX, you should have two resource groups. One of them should be for your servers, the other should only be for the vMX. You should also create the VNet you want the vMX to be in ahead of time and place this in the first resource group - NOT the RG that's only for the vMX.
2) Pick the VNet that is in the first RG. This will be the VNet that the vMX gets an IP from. I use a dedicated subnet in the VNet just for the vMX.
3) Add multiple subnets to the VNet. As an example, I use the 192.168.0.0/16 address space for my VNet. This is set on the "Address space" page under the VNet. Under the "Subnets" page, I then have multiple /24's defined (within the 192.168.X.X space). One of these I call vMX-Net and it is the /24 I use for the vMX and nothing else.
One other thing - when you create the route table for the vMX, you should create this in the RG that is only for the vMX. Don't create the route table in the RG you use for other servers. After you've deployed the vMX, don't add anything else to the vMX RG.
MRCUR | CMNO #12