Passing vales from former to formally (setting defaults)

Hi,

I'm currently looking for a way to pass data from various fields to populate on the subform from another entity.

In this case, whenever a new appointment is created from the account form, I would like to populate the location field with the account adress field and the appointment subject with "visit "+accountname in the appointment form.

Couldn't get it to work with a workflow. It stays empty ...