Building my first custom computer!

iv been saving up money to build my first custom PC. my budget is around 800$ give or take.

im fearful of buying the wrong things or that doesnt work or something like that. can someone please help me out with this venture? maybe suggest parts and a list of things that i need in a list like: motherboard, video card, memory, harddrive, etc. so i dont miss anything and etc. thanks. maybe a link to a tutorial building a pc.