Once you have your table filtered and columns hidden as needed, there are seven additional columns that aren't normally shown, but, can be added: Location, Category 1, Category 2, Category 3, Instructors, Duration, and Room.
You will use the parameter &showcols=x where x is the target column that you want to add to your table.
Multiple targets can be used by separating them with a comma.
Add three extra columns into the table: Cat1, Location, and Instructors.
Table created by adding (showing) the targets above
NOTE: The order of the columns going across the page left to right is SET and can't be changed. The order of all 19 available columns is this: