Speedretopo
How do I stop a Retopology?
Just set the Object Mode.
Be sure to remove the shading settings like "In Front"
With Besurface How do I draw a line?
Press D, and Keep pressing it to draw the Line with LMB.
To remove a line, do the same but use RMB
Invert if RMB is set as Default Click
Do I need to install Some add-ons?
The Add-on uses Bsurfaces and Looptools, you need to Install them.
You can use the Add-on without them.
How do I continue my retopology?
Just Enter Edit Mode, check if the Reference object is set or set it, and continue your Retopology.
Can I use Blender tools to make my Retopology?
Yes, the Addon allows you to use any tool you want, it doesn't use a specific mode you are locked in.