It's that simple. The first three come in pairs. They mark up text and are nested within the body tag. The image tag is not paired. It gets inserted where you want the image to appear.
Images are separate computer files that almost always end in either .jpg or .gif.
As long as you have a legal page , the browser will display the rest as best it can. You're going to learn to read and to write HTML at the same time because you can't do either well without the other. After reading the notes below, you might want to learn more about web page anatomy before going further. In these examples, I use all lower-case. Spacing Within p and h tags, spacing matters.