Here's the most important thing you need to know about a compass: There's no point in having one if you don't know how to use it. Your compass should come with directions on how to use it. Read them.
Because the needle of a compass is magnetized, it will always point toward magnetic north. You can use a compass without a map, if you just need to go in a very general direction in a straight line. But when you're in the wilderness seeking out a specific destination, you'll need a little more direction than that.
Pairing your compass with your map will give you more accuracy. It'll also alert you to any areas you won't be able to cross straight through, such as a river or a canyon. A map gives you directions, and a compass enables you to follow them. It's best to utilize a topographic map when hiking and exploring.
If you know where you are on the map but you don't know how to get to your destination, use your compass to take a bearing. Your compass lets you assign a numerical direction -- a bearing -- to any direction in the full 360-degree circle around you. This is important because, with a bearing, you can travel toward a specific spot instead of just in a general direction. Here's how to set a bearing. Your compass has a rotating ring around it. You'll see the ring is divided in increments that add up to 360 degrees. Align your map and compass both North, and place your compass over your location on the map. Imagine or draw a straight line from the compass center to your destination. The travel line on your compass will show a bearing number. Following that exact bearing will take you to your exact target on the map.