If you need support from Yola please contact us via firstname.lastname@example.org or make use of our live chat service! We are working on a new approach to community-based support and during this transition period we are not adding any new threads to this forum. Many thanks to everyone who has participated over the years and we look forward to unveiling a new peer-to-peer support system soon!
Right now we do not support drop down boxes such as you are requesting which would hide certain content on the page. Although it is probably not quite what you have in mind, here is a link to a tutorial which gives you an alternative way to handle sub-pages: Creating Subpages.