This is not a new stuff. You can get some tutorials from Internet. And it is very interesting when I did this, because I learnt new things. The following procedures are based on what I remembered. So, it may not be 100% accurate, since I am a forgetful person. 😅

What I did was reading the Arch Linux Wiki page. Then, followed the instructions as much as possible, and do some trials and errors. Remember to backup everything necessary. And try this at your own risk.