It is now possible to create a new assembly type within a project without needing to import or copy and amend an existing one.

Open the Assemblies library and select the + Add Assembly Type option at the top of the sidebar:

In the pop up that appears, select the Attachment Type, and number of cables if applicable.

Attachment Types include:

Selecting Strain allows you to set differing number of cables on each side of the assembly:

You can then find and amend the assembly in the same manner as any other in the Library.

For more information about working with Assemblies see Assemblies Library.