This is a Calibration Matrix for the Prusa Mini to calibrate the first layer. It consists of 15x15mm squares that are 0.2mm tall.
The Squares are layed out into a 4x4 Matrix and are printed sequentially starting form the front on the right.

You can create the G-Code for the Filament that you want to calibrate and start the print. Using the external perimeter you can start to do the rough calibration with the Live-Z tuning option.
Then you can adjust the Live-Z values while it prints the individual squares and check that square visually and with your finger after it starts to print the next one.