Many hobby machines do not have automatic homing and homing switches.
However the machine still needs a home because all the Gcode generating software assumes that there is one and that it conforms to certain safety standards.
The 'fake home' must be at the positive ends of travel for X, Y and Z.
How to do it? Much has been written....

How to 'Fake the home'
The is no place like G53 G0 X0 Y0 Z0
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