Travel by metro is quite simple in Paris. Indeed, the network is big and there are a metro each couples of minutes during the rush hour, and you needn't to wait more than 5 minutes in normals hours. The metro closed at 0.45 in the morning and open early.
Paris is an International city, so don't worry, you have always informations in English. If you get lost, you can try to ask someone in English, French people are supposed to learn it at school, so they can help you.
First one and above all, you must know the name of the station you aim to reach, next, let's check the station you are, and organize your travel !
In each lines you have 2 directions. Both have opposite directions and bring you in different places. The end line is indicated by a number, which is associated One in the east for exemple, and one in the west. Normally, directions are quite good indicated.
I think an exemple can make you understand simpler :
So, If To reach the blue station, I have to take "Pont de levallois bécan" for direction.
Now, Mostly, you have to get off at a station and catch an other line.
The station where you can switch are indicated by a empty circle like this one
Note than the more circle is important, the more lines converge to this station.
Now let me show you a real exemple. I admit other ways could have been simpler but this one is faster because you use a high speed line with few stops
So what I did :
I took the directions to : "St Lazard, Gare Saint lazard", Line 14. I got off at "St Lazard, Gare Saint lazard", then, I switched line, number 12 to "porte de la chapelle" and got off at the indicated stop (Maly dormoy)
It can seem complicated, but in fact it's really easy, you just need to experiment how it's work by yourself, and you should get used to quickly.
IMPORTANT ! When you buy a ticket you can go EVERYWHERE in Paris. Keep away the exit gates if you are in transit into a station, if you get out you would have to buy an other ticket, so avoid it ^^.
You can compt about 1 minute by stations (If you want to know how many time your going to spend in)
Ticket's price : one 1.40 Euros ( I guess about 2 A$), 10.70 E for 10 trips (about 15 A$)
Map :