Pretty much what he said just up there.
You have a chain spinning around a bar with a slot in it. You need lubrication to prevent the metal wearing - moving metal on metal gets hot, oil reduces the friction. It still will wear and eventually need replacing, but the oil really extends the timeframe for replacement.
Check to make sure there is oil in the reservoir, and I like to hold the saw so the the end of chain is just off the timber I'm about to cut and pull the trigger to spin the saw. If it's feeding oil you should see some expelled oil on the wood, this will tell you the oil is feeding properly and you are good to cut.
The other thing you need to be aware of is how tight the chain is, too tight and you create extra friction, which creates heat which means wear. Too loose and the chain comes off. Read the manual about adjusting the bar for chain tension. Once you are aware of this it's pretty simple to work out which I'm sure you will quickly.
Go to youtube, how to use a chainsaw and how to sharpen a chain. It's actually pretty simple stuff once you know what to do. First time you run the chain into something you shouldn't like dirt or a rock, I'm guessing you'll use similar words to which I use, it happens unfortunately - but hopefully not too often.
Enjoy and be safe.