Removal and installation of the Wrangler JL 2.0L ECU is very simple.
First, disconnect the battery terminal grounds (there are two that need to be disconnected). One uses a 13mm socket, loosen this nut and remove it (on the right). Then lift this battery terminal off its connection.
Loosen the main battery fastener with a 10mm socket, and remove battery cable.
Now, you can disconnect the ECU connecters. Do this gently, they are fragile plastic. Carefully lift them off the pins of the ECU and move aside.
There are four bolts holding in the ECU at each corner. Use a 10mm socket, loosen and remove each one.
NOTE: the top left hand side bolt has an ECU ground strap sandwiched between it and the ECU. Make sure this is reconnected when you re-install the ECU.