The CPU or the "Central Processing Unit" is arguably the most important and the part that defines how good your computer is. This runs what you tell your computer to run, including your operating system, i.e. Windows, Linux, or Mac. Without this part, you cannot do much with your computer but turn it on, and in a lot of cases, not even that!

The APU or the "Accelerated Processing Unit" is a CPU and GPU in one, all you need to know is that an APU can send a signal to your screen without a dedicated GPU, so note that some CPU's cannot send a signal to your screen!

I believe it is important to choose and get a CPU/APU that will last for what you want it to be used for now or the future.

The RAM or the "Random Access Memory" is a component that is required for your CPU to run things properly. This is what allows your CPU to do larger tasks or even simple tasks without slowing itself down too much. Many people don't realize that CPU's have built in cache which acts like RAM but at a super small scale and much much faster (and expensive). RAM isn't as fast, but you can get a lot of it in a larger quantity (Gigabytes instead of Kilobytes). In a computer, RAM allows you to run more than a simple game of pong, which includes your operating system, google, games, and even servers. 

The HDD (Hard Disk Drive) and SSD (Solid State Drive) are components you computer may use to store your data. This includes your operating system, games, files, pictures, and more. This is how your computer knows that it has stuff to be used in a computer. The difference between these and RAM is that RAM is for when your computer is actively doing something and SSD/HDD's are for long term/computer off storage. This is the part that can holds all of the information you give to your computer, without this, the computer doesn't know what you want it to do after it turns on. In most cases, this is where you see the largest numbers from Gigabytes to Terabyte's. This is because this is what holds everything for your computer, and the most important part you need to keep if anything breaks in your computer, unless your storage breaks (which is recoverable in most cases).

The difference between the SSD and HDD is that the HDD uses a physical spinning disk and magnet to store/read/write data, these are cheaper however, they can be delicate since too much movement like shaking or even another magnet close by can damage it or/and your data. The SSD uses "solid states" which means it stores data electronically, in simple comparison, they are less prone to shaking, magnets, and in general, safer for data, however more expensive than HDD's.

The Motherboard, as the name suggests, is the circuitboard that parents all your computer parts, it makes sure that each component talks to each other, without this, you don't have a computer, just components. Motherboards vary with what components you can put in it so make sure your CPU and RAM are compatible with it.

The BIOS or "Basic Input/Output System" is what it sounds like, its the most basic thing to take a input in your computer and give an output. Usually, the BIOS is in your motherboards, and tell it and the components how to act. Sometimes the BUIS require a CPU and GPU or an APU to run, however, some motherboards might be built to run it without any components. You can configure how your components run as well as check if the computer is even working!

The GPU or the "Graphics Processing Unit" is a component that send a signal to your screen so you see something. There are primarily two forms of GPU, the dGPU and the iGPU, the d stands for "dedicated" and the i stands for "integrated." In most cases, especially a business's, the computer would have the iGPU, this means there is a GPU inside the CPU, aka you dont need to buy a GPU unless you really need it. The dedicated GPU would be a seperate part that goes into a motherboard's PCIE slot to process what the screen should show you. These typically are more powerful/faster (in general, better) than iGPU's.