An External portal is a permanent link that opens a form. Once this form is completed an instance is started with this information as input. The instance id is used as the instance name.
The form shown in the portal corresponds to the first step of the process. The first step must be an Action Step. All actions are allowed in this first step except the User Selection. Any person can fill in that form and start the instance, even if it's not a Next Matter user. In case the instance is started using the External portal, the step assignee is an external user.
Go to the trigger step configuration
Select External Portal
Select below the "Create portal from first step" option.
Copy the portal link and start using the External portal with it!
Get the QR code to start the instance if this makes it easier for your use case!