The goal is to create straight lines.
Click on start point and then on each successive points.
Finger click is putting finger on the screen, you get an cross cursor and a repeater of what is below the findger in a corner, and the position is the one where you get your finger off the screen.
Contexts on canvas actions after a click:
cancel the point
close/open the path
commit
edit previous points by moving them (which gives the repeater view as well)
Moving too close of the border autoscroll.
Tool actions: