When building a computer, the PSU is installed first, then the PSU mount. The Power Supply Unit provides power to all the components of the computer. It lives behind the PSU mount (case part), which needs to be removed before the PSU can be installed. The PSU takes power from the wall socket. PSUs are rated from 200W to 1600W and you need to make sure you have enough wattage for your system. The Modular Ports allow you to attach cables that carry power to the components. Modular means that you only have to attach the cables for the components you have. The fan of the PSU expells hot air because PSUs generate a lot of heat.
Next is the motherboard, the heart of the computer that provides the pulse that moves information around the system, which all other major components connect to. Motherboards are screwed to the case using Standoffs which hold the Motherboard away from the metal of the case. The Front Panel Headers/Front Panel Connectors/FPanel is a block of connectors on a motherboard where you attach all of the ports and buttons on your case, it controls the power on, power reset, beep code speaker, and the LED light indicators on your PC case. The IO (Input/Output) ports are where you plug in all your peripherals like your keyboard and mouse. Motherboards need enough power to run the components attached to them so they usually have more than one connector to the PSU. The CMOS Battery is used by the Motherboard to remember its settings when it has no power (even when not attached to a PSU). The HDD SATA (Serial ATA) ports are where the hard drives are connected. The Central Processing Unit sits in the CPU Socket, which has a shield that holds it in place. Chipsets are processors that support the CPU and managae how it works. Every CPU model has its own bespoke chipset that is designed to get the most from it. The PCI slots are very high speed connections to the Motherboard for PCI Cards. The most common PCI cards are Graphics Cards but can also be WiFi or sound cards. The RAM (Random-Access Memory) slots are where the system memory (RAM) goes; they only allow one type of RAM and most Motherboards have between 2 and 8 slots.
Next is the Central Processing Unit, the PC's brain. It preforms calculations based on information from some components and passes the results to others. The Processor (or Die) is the chip that does all of the calculations in the computer. It is very delicate and is tightly packed so it gets hot quickly. The CPU has pins that plug into the Motherboard. Each CPU model has its own pin layout and orientation in the socket. The CPU has a heat plate that is attached directly to the Processor, this is designed to quickly get the CPUs heat away the CPU Cooler. We open the CPU shield, put the CPU in, close the shield, then apply Thermal Paste to the CPU to improve the conductivity between it and the Cooler, and lastly we install the CPU Cooler. There are two main cooling types: Air and Water.