The hardware of your computer is all the pieces that make it work. It includes the CPU, Mother Board and RAM (Random Access Memory).
A processor does all the processing of your computer and it comes in different numbers of cores. This means that you have to choose the right CPU for your needs.
RAM is a type of memory that stores data and helps your computer perform faster. It also provides a place for your operating system to store all your files and programs.
Hard Drives are the physical storage devices for your computer and they come in many sizes. Some have a broad ribbon cable for data transfer while others use a Sata interface which is backwards compatible with the older IDE interface.
Cases are the housing for your computer and they protect all your components from heat and dust. They also help regulate airflow around your computer.
The motherboard is the main circuit that all the peripheral hardware is connected to. It contains sockets for the CPU, RAM and HDD. It has a few different connectors on it so you need to be careful when connecting your components.
Getting the components in correctly is important to the longevity of your PC. It is not easy and it takes a lot of patience but it will pay off in the end.
It is not a bad idea to ask a friend or relative who has more knowledge on computers to help you choose the right hardware for your needs. This will save you from making a wrong choice that could ruin your computer and your money.