@jackthejazzcat this system expects you to setup your own actor save ID (so complex projects can customize the plugin for their needs).
Besides checking “Save Game” checkbox on variables, you have to create on your classes a property called “SGUID” if type Guid then generate an unique value that will identify instances of your class at runtime for the save system.
Or you can ignore that and simply use “Save Game Mode” function that will automatically save a record of your Player Controller, Character, etc, all members of current Game Mode group of classes.