How to set second monitor as primary (Linux Mint 19.3)?

Question

linux

Hello.
The main screen on the laptop crashed, visibility is zero. I connected a monitor from a PC (VGA)
How to assign a monitor from a PC as the main screen or duplicate 2 as 1, so that both the panel and the start menu are like on a laptop monitor?

Answer 1

unscrew and turn off the matrix, then it will probably become the main one itself.

Answer 2

X-randr of the poucree team.