To unlock the Kidd Gloves trophy in Assassin's Creed III Remastered, you will need to collect and deliver all 24 trinkets to Peg Leg, and then complete the four missions that will unlock afterwards.
The trinkets are spread all over Bosten, New York and the Fortier. They will be displayed as a chalice symbol on the map. You can find them in the world yourself, or you can buy a map in the General store that will highlight them for you.
After you complete the final mission, a cutscene will trigger and you'll set sail to Oak Island and the Kidd Gloves trophy will unlock.