All you'll need to build the Plantagotchi are two nails and a way to plug them into the PyBadge to read the soil moisture levels. The simplest way is to use a couple of alligator clip to male header pin leads as shown here.
Plug in the Leads and Nails
Plug the red lead into the 3V Feather header pin as shown.
Plug the white lead into the A3 Feather header pin -- you may want to count it out -- it's the eighth pin from the top as oriented in the diagram above.
Note: the Feather headers are double row headers, and you can use either of the two holes that align with each of the pins.
You can also plug in your battery at this time and secure it with some double-sided sticky tape.
Next, let's code the PyBadge Plantagotchi in MakeCode Arcade!