...
Click on the "Open raw HTML editor" and insert your Velocity code at the top of the HTML code between "<!--" and "-->", than Apply and save it.
If the code is ok, you can use the macro in your email template.
...
Click on the "Open raw HTML editor" and insert your Velocity code at the top of the HTML code between "<!--" and "-->", than Apply and save it.
If the code is ok, you can use the macro in your email template.