ae91fae9_trols___Official_Terraria_Wiki__Notes
[Action] Tap Hotbar [Effect] Hotbar Control [Notes] 
Selects the item tapped on the hotbar. The hotbar is the uppermost row of the inventory, i.e. the top 5-10 slots. If it is a consumable, it will automatically be used right away.
Game controls - Official Terraria Wiki
Notes