How to setup Withholding Tax for Philippines

Hello

Please help me to setup withholding tax for Philippine settings.

Here’s what I did first, I setup

WHT business posting groups

WHT product posting groups

WHT posting setup

I am unable to take up and deduct Withholding Tax for Purchase Invoice. For example total amount is 10,000 less 10% of Withholding Tax, it should be 9000 as net amount.

Is there anyone who has a resource documentation for this?

Thanks