Folio works in the background to discover transactions in your email. From the website, you can either confirm that a transaction suggestion is correct, or manually add the transaction.
To confirm a found transaction, find it in the "suggested smart folders" list and click the "ADD" button. Suggestions are deleted after 30 days if they are not confirmed.
To create a transaction manually, simply click the "Add Smart Folder" button.
If you're using the Folio Gmail Chrome extension:
Click on the Folio dropdown button above your inbox.
The folder titles that are in a light gray are suggested folders. In the screenshot below, "1121 Ventura Dr" is a suggested folder. You can click on the title text to be taken to the folder, where you can accept or reject the suggestion.
Otherwise, you can click on "Create a Smart Folder" to create a new folder.