capttim,
Congratulations and welcome to the world of Side Imaging!
What Navionics chip do you have? You may need to change your Chart Select setting in the unit.
Post some pictures for us! We all like to see how others have their units installed and will help newbies who are wanting ideas as well. And don't forget to post some snapshots when you get out on the water.
Look forward to seeing you on the forum!
Robert