Whenever you set at least one item, in the "Print header format" it eliminates display of LON-CAPA's default header. In the "Print header format" select what you would like to enter. There are two types of item:
A "substitution" item means whatever you chose from the dropdown list will be included with the value appropriate for that student. The choices are: student name, course ID or assignment note.
A "text" item means the text you enter in the textbox will be included in the header.
You can enter as many of each type of item as you like (although you are only offered "New" substitution item or a "New" Text item each time - to enter many you need to add one, click "Save Changes" then add another etc.)
The dropdowns: <m> < 1 > < 2 > </m> etc. can be used to re-order the items in the header.