Watch the video below.  Note that for the certamen machine you only have to use female wire connectors.  You can use a plier to crimp the back end of the wire connector onto the wire.  For the front end, instead of using a male wire connector, you can just directly insert the pin from the button, end of resistor, or stripped wire, and then clamp it with a plier to stay in place.

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Video:

https://www.youtube.com/watch?v=eg9hjqkJWmg