Your project for dashboard should be on the Getting Started window. If not, you need to install the FIRST update. There are tutorials on ni.com/FRC that discuss the custom dashboard, and I'm pretty sure FRCMastery has a video tutorial too.
You may want to look at the new tutorial
http://decibel.ni.com/content/docs/DOC-15144 which describes how to have a faster and bigger image sent back to the dashboard.
Greg McKaskle