Bare wires are not indicated in diagram but are connected together and if a metallic electrical box then ground to box. Non-metallic electrical boxes do not have a grounding screw so just connect all bares together and put an insulated wire nut over them. If the fixture has a ground screw or a green wire, ground it also. If the switch has a green grounding screw then connect it to ground also.
Should there be more than 1 fixture being switched, attach the next cable going between fixture 1 & 2 pigtailed to the black/white wires at fixture 1. Should the circuit need to be continued on - unswitched from the fixture then connect the onward cable to circuit power supply black/white/ bare.
The onward unswitched power cable from the switch can supply power to outlet plugs, or another separately switched switch/fixture portion of the circuit, in this case the onward cable becomes the circuit power supply cable for the next switch and fixture portion of the circuit, and refer if needed to other diagrams /instructions on this site depending on what the kind of switch/ fixture arrangement the onward cable is feeding (2-way/3-way/4-way/power at switch/power at fixture, etc.).
In reference to existing installations where you desire to expand the circuit onward from the switch, rather or not you can do this will depend on rather or not a neutral (usually white wire) and a hot circuit wire is available at the switch location. A switch would certainly have a hot wire at that location but not always have available a neutral wire. Don't assume that the presence of a white wire at the switch location that you have a neutral wire available.
If the only white wire is connected to the switch itself then it would most likely be a white wire serving as a hot wire and not actually a neutral except in some cases where specialized switches are being used where a neutral is needed to make the switch illumination work. According to code , white wires serving as a hot wire must be re-identified by wrapping a piece of black electrical tape around both ends of the wire, however in your case the absence of such re-identification may not necessarily mean that it is not serving as a hot (and it just was not re-identified with black tape). One of the things that can help you is that if there is only one electrical cable entering the switch box and both white and black wires are attached to the switch, then THERE IS NO NEUTRAL AVAILABLE AT THIS LOCATION, and the circuit power supply is at the fixture.