The installation is the key thing. This is where you connect your MacENC hardware signature to the chart encryption service.
See the picture below for some guidance on completing the form. The important element is the ENC User Permit field: MacENCx64 creates this permit code for you based on the Hardware signature of your Mac. From within MacENC, choose File => Chart Manager, then see at bottom the ENC User Permit. It will be in the box, alpha numeric, and roughly 28 characters long. Copy this and past the code into the field in Chartworld.
MacENCx64 is a two node license. That means you can run one copy on two computers. Either as a backup or one on-board and one at home.
Chartworld also supports two installs. They call this BACKUP. When you are creating the installation, you will need the ENC User Permit number from each of your different copies of MacENCx64 ready ahead of time.