Do I need to use a press to install this, or does it bolt straight on?

This bolts directly to the factory mounting points—no press required. Just unbolt the old hub, bolt this one in, and reconnect the brake line and ABS sensor harness.

Does the bearing need to be repacked with grease before installation?

No. The bearing cartridge comes sealed and pre-greased from the factory. Do not attempt to repack or disassemble it—that compromises the seal integrity.

What if the ABS sensor doesn't trigger after installation?

Check that the sensor harness is fully seated in the connector and routed away from moving suspension parts. If the code persists, the sensor ring or wiring may have taken damage during removal of the old hub; have the harness inspected for continuity.