The chest or in a more scientific term, the pectoral muscles, is one of if not the most flaunted muscles in the body due to it being easily flexible. The muscles look like this:
The purpose of the pectoral muscle(s) is to stabilize and move the arms in addition to protecting most of the rib cage. The pectoral muscle is mostly used when pushing things, hence the name of the most popular workout, the push up. The muscle is put into three sections known as heads: the upper, middle, and lower heads. 
Each is used in different motions and workouts respectively. The workouts the focus on the chest is used when pushing things and when pulling things in certain positions. Before I talk about each head individually, most of the workouts revolve around three essential exercises that are used for every head . These exercises are cable pulls, flies, and bench presses.
To start, flies are done by grabbing two handles attached to cables and pulling them in front of you from a stretched back position.
This exercise works and strains the whole chest muscle. This chest workout is good, but the equipment is usually only found in public gyms.
Next, flies are used with dumbbells, and the exercise is done by laying down and putting the dumbbells above your chest and while keeping your arms slightly bent, lowering your arms and opening your shoulders. This motion will look like this:
While laying flat this exercise will work the whole muscle. If you wanted to specialize in the upper or lower pectoral, you adjust the bench to either raised or lowered. Raising the bench specializes the upper chest and vice versa.
Finally, bench presses (arguably the most well know) is done by pushing a bar with weight above your chest. You lay down and put your hands shoulder with apart on the bar(or put the dumbbells shoulder width apart) and push the weight up. Alternatively you can use dumbbells instead of a bar. Just like the flies, you can adjust the bench to work either exclusively the higher or lower pectoral. The exercise should look like this:
The chest is one of the biggest and most powerful muscles in the body, and it can work fairly simply. The chest muscle is also one of the most useful muscles ass well, so it is fairly important that is worked regularly to keep it in good shape.
I thought I understood the basics of weightlifting, however, I did not know the pectorals could be broken into three “heads.” I have done all of the exercises that you have stated, but I really like the diagrams. It’s a nice addition that shows how to do the exercise properly. One thing that might be worth noting is to have someone spotting especially when doing the bench press.
This is an interesting blog topic! Personally I am trying to get more into going to the gym and learn how to use machines and things like that, but reading your post made me realize I definitely think more about the aesthetics of things than the specific functions of the muscles so that was interesting.
It was chest day for me today! Even though I frequently lift this was all fairly new knowledge for me. I was unaware that the chest could be broken into parts. Before I started lifting I didn’t even know that there were exercises that specialized in upper or lower pectoral muscles. I thought your chest was one major muscle group. This blog is so interesting and I cannot wait to see the next post.