How to Craft and Use a Smithing Table in Minecraft (Updated! 1.16) | Easy Minecraft Tutorial
To upgrade your diamond gear into netherite take them to a smithing table. Right click the smithing table to open the UI. Place the diamond tool/armor you want to upgrade in the left slot and the netherite ingot in the right slot. As you can see the helmet keeps its enchantments and becomes a netherite helmet.