This guide is going to show you how to build an Ethereum Mining rig yourself which has two main steps - choosing and sourcing your equipment and then putting it together! Depending on times its probably going to take you a week or so to get all the pieces and then another half a day fiddling with configurations etc. Its the same as building your own computer normally but with a few extra considerations that mainly involve which GPU's you pick.
https://www.cryptocompare.com/mining/guides/how-to-build-an-ethereum-mining-rig/