Exclude a subdirectory on copy

I have a directory tree that I want to copy, but I want to leave out a subdirectory; very similary to using rsync -r with an --exclude option. How can I do this with dopus?

You can use the Copy Filter, and make the filter use a sub-folder clause (also described in more detail at the bottom of here) which excludes the unwanted folder.

Sorry to be ignorant, but I do not know how to "use a copy filter". I have seen dopus references to such commands, but I have never understood how to actually use them. If it is not already part of the dopus menu system or something trivial (like add a button for opening selected file in emacs), I do not understand how to execute dopus script commands. Do I have to make a button to do this? Is there a simple way to execute this "copy filter" in an ad-hoc way using the dopus menus? I appreciate your help.

If you read the documentation that Leo linked to it explains how to use it.

"When copying or moving files, filtering is enabled by selecting the Copy Filter option in the drop-down attached to the Copy Files button. The copy filter is local to the Lister, and it remains enabled in that Lister until it is turned off or the Lister is closed."

Thank you! After your answer and re-reading the documentation a few times, I was able to use the copy filter operation to meet my needs.

Don't forget to disable the copy filter after you're done, if you forget it stays activated until the lister is closed.
That's why I have a dedicated "Filtered Copy Files" button, which simply uses this code: Copy FILTER