Modules are parts of your layout, included as full sections in your layout.
In Use
Modules is an easy way of including the same content or feature in many place off your theme while still editing in one single place. When you create a new section in a layout, you can choose to use a module. Modules that are included in one or more templates as listed as ’In Use’. Each instance of the module will be updated when changing it.
Unused
Modules that are not part of any template are listed under ’Unused’. These modules can be a small library of custom section you will be using many times, but with small variations.
Once a section is added and a module has been used, you can detach the section from the module, making the contents part of your layout with no relation to the module.
Blueprints
Blueprints are standard sections that can be added to any layout. When a blueprint is used for a new section, the parts of the blueprint are added as static elements in that layout. In contrast to the Modules, blueprints are not linked to a single source, however after including a blueprint in your layout, you can easily save that same section as a module and use it repeatedly as explained about.