You can go to the extraction section by either clicking on the administration icon on your top right corner and clicking on "Add-ons", or by simply typing "g+g" and searching for "Import Attachments". Once you are in the import section, you will see the below screen:
Now all you have to do is choose the file that you have already downloaded from a second instance and then AMJ will parse it and show all the projects that this file contains, and you can choose what project attachment you want to import.
And once done, you will get a report of how many attachment issues were imported in each project.
