Setting checkbox on using drop down menu as a guide

Hi there,

This is my first try at forms using Livecycle Designer. I am trying to get some checkbox to be checked depending on what value is chosen a drop-box menu.

Example:

Dropbox on page 1, fieldname: department. If a user choose administration, it would check on page 3 the checkbox named openoffice, and another one named worldclient. if in the dropbox they choose another choice, it would check other fields.

I tried looking around a little but I am a bit lost. :(

Thank you very much for any help you can spare on that to get me going. Never thought we could do so much using Pdf forms.

Mike B.