Turn off power at the breaker and verify the circuit is dead
Identify the line hot, load, and the two traveler wires
Connect the line hot to the common terminal on the first 3-way switch
Connect the load wire to the common terminal on the second 3-way switch
Connect the two traveler wires to the traveler terminals on both switches
Connect ground wires to the green grounding screw on each switch
If neutral wires are present in the box, keep them tied together and not connected to the switch
Secure all wire connections with approved wire connectors
Mount the switches back into the boxes
Install the cover plates
Restore power at the breaker
Test both switches to confirm proper operation