Tab and Slot - slots for tabs that already exist?

Stap 4: Selecteer de onderzijde van het andere part tot waar de tabjes ge-extrudeerd moeten worden SOLIDWORKS tab en slot assembly tabs

So I cannot figure out how to add tabs and slots to my assembly The “insert > sheet metal > tab and slot” path is only available within the

solidworks slot callout Creating a Tab and Slot · In a part, click Tab and Slot or Insert > Sheet Metal > Tab and Slot · In the PropertyManager, specify options

solidworks tab and slot in assembly SOLIDWORKS 2018: What's New