Open ArcMap
You can either browse to maps when first starting ArcMap to open them or if you have already been working on maps previously you can open them with the following:
The folder icon in the top left
File Menu then Open
With each of these options you will need to browse to the folder of interest. If you are working with Casco Bay browse to the drive that you mapped \\microwave\research\CBGIS to and then look under the \GIS files\Project Files\ folder. If you are working with Long Island data you can look under the original data\LongIsland Data\ folder.