Make sure that you're logged into Cloudtrax with your Master Account. Your Master Account is the account that contains all of your networks underneath it. If you're unsure of what your Master Account login is you can use the Lost Login form to recover it, or contact Support.
Click the Network drop down menu to see your list of networks. To create a new network simply click "Create new network" and follow the prompts from there.
If you have old hardware (OM1P, MR500) you will need to select "Create Legacy Network" for those devices to work. Otherwise leave it unchecked.
To delete a network switch to that network with the drop down menu and go to Configure->Advanced. There you will find a button that says "Delete This Network". Click it and then type "delete this network" into the box and the network will be deleted. Any MAC addresses tied to that network will be deleted and free to use on any other network.