On every computer listing, there are always the parts. The indecipherable description of these parts (think "8GBGDDR6RAM") can be daunting at first. However, we will try to help you understand computer parts better so you can make better choices around buying your next computer.
CPU: Your CPU is your processor. It's often referred to as the brain of your computer. A better CPU will make all of your computer processes faster. The main brands making CPUs for PCs are Intel and AMD. Your CPU choice mainly depends on how many cores the CPU has, and the generation. In your computer, there is at least one(usually two) cores running equations at warp speed to make your computer function. However, if you have more cores, naturally the cores can work at the same time as each other and therefore process more information in a smaller amount of time. A quad-core processor is good for fast day-to-day tasks or gaming, but for hardcore games or video editing, you'll want six to eight cores.
Cooling: If you search for CPUs, you'll notice many of them include a cooler. The cooler is necessary simply because with all the computer parts running so quickly, the case gets extremely hot. To prevent your plastic parts from melting or a fire from starting, you need cooling. There are two main types of cooling: water and air. With water, you have tubes filled with not pure water, but a mix of cooling chemicals akin to some ice packs. Water coolers are generally harder to install. With an air cooler, you can simply screw it on top of the CPU, or wherever else you want it, and the fans start running. Water and air coolers also come in variants that have RGB lighting.
GPU: The GPU, or graphics processing unit, or graphics card, is one of the most integral factors of your computer's performance. The GPU is kind of like a separate computer from your PC and handles all graphical performance-related tasks. Computers with weak GPUs (cough, cough, MacBook, cough, cough) will seem laggier and might be a bit choppy when playing games. GPUs have their own kind of RAM called GDDR. Right now, the best on the market is GDDR6, so don't get that confused with normal DDR4 RAM. Almost all processors have graphics built into them, which are decent, but not good enough for gaming or video editing. When graphics are built-in, they're called discrete graphics. When you get your graphical performance from a GPU, it's called dedicated graphics. If you have dedicated graphics, your monitor will plug directly into the graphics card instead of the motherboard. The most popular manufacturer of graphics cards is NVIDIA.
Motherboard: Your motherboard is what holds everything together. You attach almost everything to your motherboard: Your PSU (power supply), RAM, CPU, cooling, and more. Additionally, you know all the ports in the back of most PCs? Those are connecting directly from the motherboard. Most modern motherboards have around 5 USB 3.0 ports for all your peripherals. A big criterion for motherboards is what size/shape they are. The standard for motherboards is ATX, so you should do some research into how your motherboard will fit in your case. You should also research if your motherboard is compatible with your processor, as the processor fits in through a processor socket (an array of hundreds of pins).
RAM: RAM is an essential part of making your computer's performance. You can think of it as your computer's short-term memory; it stores recent information and information it will need soon. The reason there is always so much less RAM than storage (i.e. SSD, HDD) is that RAM is much more expensive because it is much faster. Your computer, when doing any action, will pull related information from your storage into the RAM to be accessed on a moment's notice. When you shut down your computer, all the data on it is either wiped or committed to long term memory.
PSU: The last main part of your PC is the PSU, or power supply unit. This is exactly what it sounds like, providing a certain wattage to your computer depending on how much you pay. The nicest PSUs can manage over 1000 watts, an unnecessary figure. What you need to do if you are building a PC is to figure out how much energy each part takes up and get a PSU that can produce more energy than that amount. If you are buying a prebuilt PC, this will already be taken care of for you.