Install OT gear through Body Hack at Ink on the Brain, Acelino's shop in the shopping mall. Bring back OT Parts from the dungeon, develop the equipment there, and equip it before the next dive. A part in your inventory is a crafting resource; it is not automatically an installed upgrade.
Go to Ink on the Brain
- Return to the shopping mall between dives.
- Visit Ink on the Brain and open its gear options.
- Check the equipment you can develop with the OT Parts you have collected.
- Develop the piece you want, then place it in the matching equipment slot.
- Inspect the resulting skills and effects before leaving for the dungeon.
Read the effect, not just the part name
OT equipment can add passive effects, conditional automatic skills and active combat options. Check what the specific piece actually grants. A useful passive and an additional attack serve different purposes, even when both come from the same crafting system.
Body Hack equipment continues working while Davy changes Styles. You can therefore prepare gear around the way you intend to fight instead of treating it as equipment reserved for Zombie form.
When you cannot develop the piece
Inspect its displayed requirements and the facilities currently available in the mall. More preparation options open as the story progresses; the shop's presence does not mean every equipment function is immediately unlocked.
Keep OT Parts separate from Bessie Burger's skill purchases. The two shops strengthen different parts of your next run, and spending time in the wrong menu will not install a piece of equipment.