Man... man... man... you're all over the place, lol!
No hurry, take your time...
Key components of a PC:
- Power supply: you NEED a quality one, a cheap PSU could die unexpectdly and take some components with it (motherboard, CPU, graphic card...)
- Motherboard: it "inter connects" all the components. It's mainly defined by its socket (AMD AM3+ and FM2+, Intel LGA1150 and x99 to name the mos common ones). For each socket, there is a matching type of CPU. Some allow overclocking, some not.
- The CPU: it's the "brain" of the computer. Some allow overclocking, some not.
- The memory: All the current sockets use DDR3, x99 uses DDR4. It's rated by frequency (1333/1600/1866/2133/2400MH and so on) and latency (Cl8, Cl9, Cl10...). The higher the frequency and the lower the latency, the faster the memory.
- The graphic card (or GPU for Grahic Processing Unit): it handles the display. The higher end the GPU, the better performance in game.
- The storage unit: that can be a Hard Disk Drive (HDD), or a Solid State Drive (SSD). HDD's are mechanical, offer large storage and are cheap. SSD's are made of some kind of flash memory, are MUCH FASTER than HDD's, but price per Gigabyte (storage unit) is much higher than HDD's. You usually use a SSD for your operating system and the games/applications you use often, and HDD for data storage and applications you don't us emuch.
- Monitor: it's rated by resolution (720p, 1080p, 1440p,4K) and refresh rate (60Hz, 120Hz, 144Hz). The resolution defines the amount of pixels the monitpr can display. Most common is 1080p. Refresh rate is the maximum frames per second (FPS) the monitor is capable of.
- Overclocking: increasing the CPU speed above stock clock to have some "free" extra performance. Requires good aftermarket cooling.
- Watercooling: leave it for now
Let me have some coffee and I'll go more in depth in an other post!