Death Stranding Rest In Pieces Trophy Guide - In a BT area, cut an umbilical cord for the first time without the BT noticing. [Bronze]

First you must get the Cord Cutter - it's an automatic story unlock (unmissable) in Episode 5: [Order No. 46].
Once you got it, go to any BT area and press SQUARE to cut an umbilical cord. Every single BT has an umbilical cord. They become visible when you use the scanner R1 while standing still. BTs show up in rainy areas. After you recruited the Weather Station to the UCA (Episode 2) you can press R3 on the world map to see where it's raining. You'll frequently run into BTs though so no need to go out of your way for it.