The Inspiration Catalyst, which lets you convert Season 1 items into Tier Set pieces, will be available starting January 23, 2023. It’s located in Tyrhold on live servers.

The entrance is located at 59.53, 53.71 in Thaldraszus.

When you enter the zone, you will see an NPC named Antuka <Catalyst Steward>, with the following dialogue optionYou have journeyed far, adventurer. What is it you seek?”

I believe there will be an intro quest line when the Catalyst becomes available on live servers.