How to generate fb access token
Login to facebook (it can be your own account, or you can create a seperate account just to use it for data extraction)
Click on Get Token, and then click on Get User Access Token
You will see this screen
Select any one options from User Data Permissions and click on Get access token
Click on the button
You will now be directed to the main page, where you will see the access token ..
You need to paste this token in settings ...
Open the software, Click on settings > data > Facebook token
Please remember that your api version should be 3.0 or higher. you can see the version below. If its more than 3.0 then put update that in the settings.
you can generate multiple access tokens and paste them one below the other. this will help you to extract more data. see image below. You cannot create multiple access tokens from the same account, you will have to create multiple fb accounts. so literally, there is no limit on data extraction from fb business data extractor.