When selecting comps, you are able to make revisions by tapping the blue Choose Comps button. Once tapped, you will be presented with a grid view.
Switch between Available and Selected to see what you've selected, check bracketing & narrow down comps.
Switch between Grid View and Map View by selecting the globe icon in the middle top of the page.
When in Map View, clicking a pin on the map will open a Side Panel to compare, select, and access more data for the property.
On the Side Panel, you can choose to use a property as a comp by selecting the Use Comp button.