Click the Compare Jobs button in the toolbar to enter the compare view.
Use the timeline to select the two jobs that are being compared on the map. Double click the icon above a job to change the ortho on the left. Single click the icon above a job to change the ortho being displayed on the right.
The map is split into two parts. The left side displays the top ortho. Click and drag the circle with arrows to hide or reveal the ortho on the left. Use this step to see the entire job site has progressed or zoom in to inspect how a specific aspect has changed.