Plug in and turn on the printer

Using the screen menu, move the X axis up until it crashes into the Z tops. The stepper motors will skip, making a noise - this will not damage the motors

Using the screen menu, move the X axis down until the nozzle is approximately 10mm from the heated bed

If the X axis is stopping before crashing into the Z tops, move the X axis a little further down and power cycle your printer. You will then be able to complete the step

It is possible that with the weight of the Hemera the X axis is moving down on one side when the printer is off for some time. If this happens, move the X up until it crashes as explained here. Note that his can also happen to stock Prusa printer (and so stock Prusa extruder)