Super noob here, I'm asking this because I know Li-Pos can be quite dangerous and I don't want to set my whole house on fire 
.
I'm working on an Arduino Nano project that requires powering the board using a Li-Po battery connected between the VIN and GD pins of the board. I'd like to add a SPDT (sliding) switch in order to connect/disconnect the battery without physically detaching it in order to power the Arduino on and off... What is the correct way to wire this up without causing a short-circuit that will destroy my Li-Po? I've been looking for example circuits but I have't found any help.
Thanks!
Yes you an do that. [u]Switch basics[/u]. You'll have to "break" the circuit and insert the switch in series.
You only need two of the switch terminals, which means you'll be using it as an SPST (on/off) switch. You'll need to use the common terminal (usually in the center) and one of the other terminals.
Technically, you could say the switch creates "short" when on and an "open" when off. But when wired correctly, "short" is in the "right place". It completes the circuit and allows current to flow.
Since you normally wire the switch only to the "hot" side of the power supply/battery you don't have to worry about a power-to-ground short. If you can understand the schematic you should be OK.
Thanks for your reply! Yeah I took a look at that article, but it still didn't quite clarify it for me... Say instead of using an SPST I'm using an SPDT switch and I want it to act like an on/off switch. Do I connect the common pin to the positive battery lead, and one of the other two pins to the power input of my circuit, and leave the other pin unconnected? Or does the other pin need to be connected to ground? Thanks!
Ignore one of the terminals to make a SPDT act like a SPST.
When using high current batteries like LiPo and lead-acid, you should have a fuse as the first
line of protection, on the positive lead to the battery before anything else. Its function is to
stop the wiring bursting into flames if there's a short circuit further on.
Fuse should be rated for the max current you need, the wiring should be rated for more than
that.
If your skill level is as low as you suggest, it really helps if you include photographs of the actual switch and its connections. A picture is worth a thousand words.