I'm getting into building a computer myself, and Ram Capacity makes it possible to procces more things at a time, and performance makes it faster (4 GB Ram has 1600 mHZ performance)
You'll need all the following components for building a computer
- Ram Memory
- Hard Disk and/or Solid State Drive (Solid State Drives generally come with low storage capacity, but have just about twice the performance speed of a Hard Disk, so this where you put the stuff you want to load fast like your operating system)
- Operating System (Windows)
- GPU/Graphics Card (Look at the pretty pictures!)
- CPU ( i3/i5/i7/AMD they come with various names single, dual, quad, hex cores, the more cores the better)
- CPU Fan (you don't want it overheating, do you?)
- Motherboard (Connects everything!)
- Case (Cardboard box is optional but not recommended)
- Power Supply (Your stuff needs some juice to run on!)
- DVD Drive (where else are your disks going?)
Look on youtube for videos that show you how to connect everything, I'm crazy, and cya :D