Slide the Z motors in the z_motor_mounts. The motor cable should be oriented towards the inside of the frame (red lines on the images).

The Z motors have different cable length. The motor with shorter cables must go on the side of the dual Y axis bearing (left on the images).

Secure the Z motors in place with 8x M3x10 screws (reused from your original Prusa). Press the motor in the direction of the yellow arrows while tightening the screws evenly, incrementally and in turn.

Note that the previous, Bear 2.0 ''z_motor_mounts',' used M3x12 screws and they will be too long for these new mounts.

Previous version of Bear or Original Prusa are using washer on the M3x10. This is not useful anymore, you can discard them.

Check the orientation of your motor cables.