If checked, Jenkins will run individual module builds as separate builds. On a project with a large number of modules, or on a project where modules take a long time to build, setting this option to true may speed up the whole build, as different modules can be built in parallel.

In this case the specified ant targets will be called on each module separately. Also, all of the post-build actions will be run per-module and the paths you specify in their configuration should be relative to the root directory of each individual module.

Otherwise, leave it unchecked and Jenkins will build this Ivy project like you'd normally do from command line.