Step 1: Get your personal access token
In Airtable, go to https://airtable.com/create/tokens.
Add a token name.
Add a scope and select all the following Scopes (data.records:read, data.records:write, schema.bases:read, schema.bases:write)
Copy the token (if you didn't copy down the token the first time, you can regenerate it with the [...] icon to the right of the token list.)
Step 2: Create a Grid on Airtable to store your data
Step 3: Get the BaseID and TableID
On the page with your Grid, you'll see a URL in the browser bar with the following format: https://airtable.com/baseID/tableID/ignore-the-end
Copy the Base ID and Table ID
Step 2: Connect to your Airtable Grid to Run
On the Run form builder, click to add destination, select Airtable, and then enter token, base ID, and table ID. Confirm that it's connecting correctly under Status after you save.
Step 3: Enable Airtable on ALL forms you plan to use
On the form builder, you must click on the Enable checkbox to the left of the destination for all forms you want to use this destination for on the site.
Custom fields must be created on your Airtable account directly by going to your Grid, and adding a Single Line Text or Long Text field.
In order to add custom fields to your form, open your Run form builder, click Add Form Field, and add a Custom Field (like 'text' for example). Under the Airtable custom fields column, Run will pull down a list of your custom fields from Airtable to select from.