If you have a separate filtered view configured in Airtable for each of your potential portal users (e.g. one filtered view per vendor, client etc) you can automatically generate a users table for your portal! Here's how:
Start creating a portal
Select "No" to the "Do you already have a table that lists all the users for your portal?" question
Select "Yes" to the "Do you currently have separate views set up in Airtable for each of your users?" question
Pick the Data table that contains the per-user views
Select the Views holding the records for each individual user
Click Continue
If you now click Start Migration, we will automatically create a new table (called "miniExtensions Users") in your base. The users table will be linked to each existing table in your base so you can use them all in your portal. A user record will be generated in the users table for each view selected in step 5. For the chosen data table (step 4), each record in the selected views will be linked to their respective user record.
Finish setting up your portal.