Creating custom audiences is easy with Filed.
First create a spreadsheet in CSV or TXT format with either email addresses or phone numbers using your customer data.
Go to Audiences Tab and click "+ Create Audience".
Click File and upload your spreadsheet file.
Order your columns according to name fields, name your audience and click "Next".
Your audience is created and you can see it in your Audiences list. Remember to check availability. If it's too small, Facebook won't be able to utilise it.
