How Aperture Affects a Photograph
The smaller the number; the smaller the focus range. The greater the number; the greater the focus range.
If you can remember the first two sentences you will have a pretty good idea how to treat aperture when you look at a camera. The aperture of the lens is important beacause it describes how much light hits the sensor by giving a number to the iris's opening in the camera lense.

Before you get bored on the technical jargon take a look at the gif again. The smaller the aperture the smaller the focus range. Out of those two shots in the gif one of them has a smaller plane of focus meaning it had the lower aperture setting. I used the setting of f/2.0 to bring the focus onto less of the needle ice. Then I switched to f/7.1 to extend the range of what was in focus. I could have gone higher and had more in focus, but I neglected to bring a tripod to keep my camera stable.
Got it?!?! The smaller the number; the smaller the focus range. The greater the number; the greater the focus range. One other thing that makes this work out. As you can imagine since one lets more light in than the other (lower f/ means more light) you have to compensate some how.
When you have the higher f/ number you have to set the shutter speed longer to allow more light to expose your sensor. This is where the tripod comes into play. The camera needs to stay stable longer with the smaller opening of the iris. I like to set my camera on aperture priority and not have to worry about the shutter speed.
In the end. Choose what you want to show in your image. If you want to show more of the surroundings, chose to have a higher f/ setting for your aperture and expect a slower shutter. To focus in on a subject chose a lower f/ and need less light. (always exceptions)
Every time you take a camera out to explore the world. Make it show you, what you, want to see.