To install the extruder you have to follow external guides. As the Bear frame supports different extruders and X axes it would make this guide too long and complicated to follow. Thank you for your understanding :)

Reinstall the extruder on the X axis by following the external guide(s) relevant to the extruder and X axis of your choice:

BearExxa (Bear extruder and X axis): start with 3. Extruder, then 4. Extruder and X axis assembly up to step 10 and finish with 5. Final adjustments and calibration up step 8.

BearMera (E3D Hemera): start with 3. BearMera extruder up to step 14, and then 4. Adjustments.

Bondtech on Bear X axis: follow our guide here.

Original Prusa extruders installation guides: MK3S+, MK3S, MK2.5S, MK3 (spiral wrap), MK3 (textile sleeve), MK2.5 (spiral wrap), MK2.5 (textile sleeve), MK2S.

Bondtech extruder on original Prusa X axis: choose the guide corresonding to your extruder on support.bondtech.se/c/Prusa.