What is composition in photography?
Composition is how the subject is arranged in the frame to allow the viewer to understand what the subject is. In the image below the subject is composed in the frame using the rule of 3rds. (The subject, the girl.) Sometimes, the design elements are used to define the subject, such as line, pattern, repetition, texture, shape, and so on.
In the next image, because the activity of the people in the image is on the 3rds, the woman burying the child in the sand is the subject. The 3rds means to put the subject on the intersecting lines where the red dots are on the drawing below.
To make the composition easy for you, go into grids in your camera menu and set the 3rds grid, then each time you want to shoot this grid will show up to assist you in your composition until you get comfortable.