a. Go to EU Login site and register yourself (as a person, not the organisation). Preferably use your organisations' general email account. You will get a confirmation email and it has a temporarily password that expires after 24 hours. Set a new password and you are registered at EU Login verification service.
b. Then, go to portal of the Erasmus+ programme. If you are still logged in at EU Login, you are automatically logged in here as well. Otherwise, use the same log in details as EU Login. Click organisations and a drop down menu appears. Select register and fill in the details. It will ask you to upload some legal documents (like registration papers, chamber of commerce, and such alike) but that you can also add/ upload later, after the deadline, as it is not part of the application procedure itself.
Submit your organisational details, and you received an organisational ID.