Select "Flatten directories" to ignore the directory structure of the artifacts in the source project and copy all matching artifacts directly into the specified target directory. By default the artifacts are copied in the same directory structure as the source project.

Select "Optional" to allow this build to continue even if no build is found matching the "Which build" condition selected above, the build's workspace does not exist or is inaccessible, or no artifacts are found matching the specified pattern. By default this build step fails the build if no artifacts are copied.