Connecting linear potentiometer to arduino
Pot is simple to connect. There are 3 terminals - top voltage (usually your Vcc), bottom voltage (usually ground) and middle terminal that outputs analog voltage you want.
Potentiometer is basically a voltage divider, where you can change the proportion of upper and lower resistor. Read about voltage dividers if you're not familiar. It's really-really easy.
What will happen, if you flip it around? What if you connect pin 1 to GND and pin 3 to Vcc? It will still work just fine, it's symmetric.
How do you know what terminal is what?
If it doesn't come with pot, you can measure resistance between every pair of wires on the pot. If you have some round number that doesn't change with pot turning, you're measuring between terminals 1 and 3. Connect any of them (1 or 3) to Vcc, the other (3 or 1) to GND, and the last unconnected lead will be pin 2 analog voltage.

Vin is your 5V, Vout goes to analog input pin of your Arduino. You can turn it around as much as you want, you'll never burn anything here.
Have fun with it :)