Auto Actions: How to obtain Variables?

Hi, I made an auto action for email notification after creating a new group wall entry with
gjint_onAfterCreateWall. It works fine. Thanks.
Now my question: How can I get in the mail the information, in which category and group is this new entry. Can I get the post too? How to put them in the email.
Is this with the "variables". Can you explain please how to use them.

How can I get in the mail the information, in which category and group is this new entry. Can I get the post too? How to put them in the email.

You can't. CB Auto Actions has no idea what variables in the trigger does what so all it constructs is the user object so substitutions can be used. If you want that you'll need to develop a new CB Plugin specific to your needs so you can utilize that triggers specific variables.