Before importing an assembly into Vertex Connect, you must first create a new folder in which to save all of the assembly files. This is required so that Connect can read all of the assembly's information. For faster imports, you can also compress the assembly into a single .zip file. Watch this video to find out how.
Important: If you zip your assembly, the filename of your zipped file MUST match the top-level assembly filename (or part name if you're packaging a single part).