When do I use the Merge and Group tools?

In some images, a single object or area is made up of multiple boxes or outlines. 

For example: there are trees in this image blocking the Vehicle Bus, so it was drawn using three outlines. 

Other times, a missing section can be added to an already outlined object. 

For example: this Ground Road was drawn in multiple sections, but it is one continuous area.

Spare5 tasks help computers to "see" and "think" better. In these images, we want to show that even though there are three Vehicle Bus outlines or two Ground Road outlines, there is only one object or area. That's why we Group and Merge. 
To Merge and Group, select each box or outline, then choose the tool from the toolbar.,
Use 'Group' when outlines are separated. 'Group' connects different boxes or outlines inside one larger box.
Use 'Merge' when outlines are touching. 'Merge' combines multiple boxes or outlines into one single outline. Be sure that the label is correct after merging.
The GIF below helps us visualize the difference between Merging and Grouping:

Important: you will only use Group and Merge for the same individual object or continuous section of a qualified object. These tools are not meant to be used for more than one object of the same class.