Turn off power at the breaker
Verify the power is off with a voltage tester
Remove the switch cover plates
Identify the common terminal on each 3-way switch
Connect the incoming hot wire to the common terminal on the first switch
Connect the wire going to the light fixture to the common terminal on the second switch
Connect the two traveler wires between the traveler terminals on both switches
Connect the neutral wires together in the box if present
Connect the ground wires to the green ground screw and bond to the metal box if required
Tighten all terminal screws securely
Reinstall the switches and cover plates
Restore power at the breaker
Test both switches to confirm proper operation