MUD stands for Manufacturer Usage Descriptions, a standard manufacturers can use to describe what sort of network access their devices need.
Each MUD file contains access control lists that use various classes. When you click on the carot next to the class in MUD maker, additional information will appear below that you can then fill out. Just choose which classes are appropriate for your devices. If you need more entries per class, hit the + button at the top of each class.
Once you've developed your MUD file, plop it on a server somewhere. Then have your device announce a URL pointing to that file. This can be done with LLDP, DHCP, or in a certificate.