Im a newb myself but I will share my though on where to start with you
First you need to decide what part is the most crucial to you, my bet its CPU (processor).
When you pick out a CPU that suits you best in price/performance departments you need to check what socket it is designed for.
Based on the socket type the CPU uses you can search for a MOBO (motherboard) with that socket type.
At the point of searching for that you need to decide what GPU (graphics card) you are willing to use and you need to confirm MOBO provides the right ports for your GPU. When you got those three all set other stuff doesnt really matter because it is to my knowledge standart and goes well with any setup.
Before buying the stuff make sure you ask someone pro to take a look at what you came up with so it isnt messed up anywhere undetectable to inexperienced eye.