How to Upgrade Your Staff of Building to Netherite
Get a Diamond Staff of Building First
The Netherite Staff of Building is not crafted in a normal crafting grid. It is produced with a smithing recipe, and the input staff for that recipe is the Diamond Staff of Building. If you are still on a Wooden, Stone, Iron, or Golden Staff of Building, upgrade through those tiers first using their shaped crafting recipes until you hold a Diamond Staff of Building.
Use a Smithing Table
Place a smithing table and open it. Put your Diamond Staff of Building in the staff slot and add the netherite materials the smithing recipe calls for. Confirm the output to receive the Netherite Staff of Building. Because this is a smithing recipe and not a shaped recipe, do not try to assemble it in a regular crafting table.
What to Do Next
Once you have the Netherite Staff of Building, you are at the top of the standard upgrade path. The only remaining staff above it is the Infinite Staff of Building, which is a separate item rather than another smithing step. Keep your Netherite Staff of Building as your working tool while you gather whatever the Infinite Staff of Building requires. If you lose your Diamond Staff of Building before smithing, craft another one through the shaped recipe chain starting from the Wooden Staff of Building.