For making the cable yourself. I do not known what to do.
Can I take for example the following piece and just take the red cable of it and connect the red wire (+5V) to a probe? And cutting off the 3 other cables?
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Links:
[URL]https://shorturl.at/vAFI9[/URL]

For...

Where can I buy a cable with one end USB type B and the other end a pen/stift?
For shorting are you holding the pin on GND already when starting up the laptop and then releasing it at a certain moment while keep pressing F1. It is not clear to me when exactly releasing the pen?
I suppose it doesn't matter to use GND1 or GND2?