Here GFCI’s are wired to a double-pole circuit breaker with the source split to provide 120 volts to two sets of receptacles. The neutral from the source is shared by both sets. Single-location protection is provided by each receptacle.
In these cases, it should be wrapped with electrical tape to mark it as hot. The ground wires will be green and/or bare copper. The ground should be spliced with a short piece of wire and connected to each device and outlet box that has a grounding terminal. In these drawing the brass colored terminal represent the hot side of the device and the silver colored terminal represent the neutral. Ground wires and terminals are in green.
In this arrangement with 2 switches in one box, the bottom terminals are connected to pigtails spliced to the source. The top switch terminals connect to the black wires running to the light fixtures. The source neutral and ground wires are spliced to run to each light box.
In this wiring, a switch and receptacle are in the same box and the switch controls the power to the outlet. The hot wire connects to the bottom terminal on the switch and the top output goes to the receptacle hot terminal. The neutral wire from the source connects directly to the receptacle neutral.