Button	Description
List	list relevant data
Add	add a new segment, tributary, or channel to the end of the list
Insert	insert a new segment or tributary after the current one
Defaults	assign default values (model options or model coefficients only)
Delete	delete the current segment, tributary or channel
Clear	clear all input values for the current segment or tributary
Copy	copy output table or graph to windows clipboard (for pasting into other applications)
Undo	ignore all edits & restore original values
Help	view relevant help screen
Cancel	ignore all edits, restore original values, & return to progam menu
OK	save edits & return to program menu

The above descriptions also appear as a 'tool tips' when the mouse hovers over a given button.