Simple Guide to Minecraft/Upgrading (Before 1.20)
This section applies to version 1.19 and before of Minecraft, an older version.
To obtain Netherite tools and armor, you must collect the diamond tool/armor variants of what you want to upgrade, and Netherite. Netherite can be obtained from smelting Ancient Debris into Netherite Scrap. Combining four Netherite Scrap with 4 gold ingots creates one Netherite ingot. Netherite can also be found in bastion remnant loot chests. With a Smithing Table (crafted with four planks and two iron), put your diamond tool/armor and combine it with Netherite ingots to create Netherite variants of the tools and armors in the game.