How to set ports in ADS2011 version

Insert -> Pin from the menu or from the toolbar.
What exactly is your question?

actually my question is how to set ports in layout of ADS2011 for multilayered antenna?Is it enough to set a single port for all the layers?

Your question is still not clear enough to answer, because we don't know what you antenna ground looks like.

Please have a look at the ADS help, where the use of ports is described. This will help you to decide if you need an explicit ground reference.

Is t necessary to set the port from the properties menu after dragging it from toolbar?

Of course it is necessary