After registering, click on your name followed by the organisation on the top right and choose "My organisations".
In the upper right corner you will find the button "Add Organisation".
You enter the company number of the organidation you wish to add.
If the organisation does not yet exist, at least fill in the required fields and follow the steps.
You will become the administrator of the organisation and will be able to work with this organisation.
If the organisation already exists in the system, fill in your employee information within the organisation and follow the steps.
You will then be put on "waiting for confirmation".
An administrator of the organisation in question will have to confirm you, this from the screen "My organisations" - "Employees".