i would have to agree with wiggy & admin, but also disagree with the video in the last joint of twisting it before the twist joint then soldering
this will cause more stress on the wire from what maybe called a double twist
I have been an auto electrician for 23 years now, only finding dry solder joints on components due to lack of heat& flow of solder,where as I have found many faults with crimp joiners/connectors & the good old scotch locks
non insulated terminals crimp & soldered are much better then just crimped but some times crimp terminals are the only way