The biggest misconception is that aperture controls shutter speed or vice versa.
If fact, the two work in concert to achieve the optimum exposure for your image.
That should be the main goal of all your photos.
How you choose to emphasize the your subject is a topic for other articles.
Essentially, the aperture and shutter speed work to provide the proper ratio of light.
If you select a larger aperture, smaller f-stop like 2.
8, you are allowing more light through the lens.
This in turn allows you to use higher shutter speeds to capture motion without blurring.
Keep in mind that that the smaller the f-stop, the shallower your depth of field will be.
An object in the background may appear blurry with a large or open f-stop but appear in clear focus with a small or closed stop.
So in general, here's where you want to be with your aperture setting for various types of photos.
For portraits, you will probably tend to start more to the open end of the setting, meaning a small f-number.
This is useful if you are trying to eliminate background distractions because of the shallow depth of field.
On the other end of the spectrum would landscape and architectural images.
Here you will probably start with your aperture closed down as small as possible to get the greatest depth of field.
With this genre of photography, smaller apertures are necessary due to the size of the subject and the proximity of the camera.
But you will need to use much slower shutter speeds so a tripod and shutter release cable are useful to have for these shots.