If you want to do it properly and safely, it is NOT an easy task and requires quite a lot of knowledge on software and hardware, just watching videos is not gonna be enough if you want to it 100% correctly to avoid fires, short circuits, cards dying in days or hours and things like that.
You should talk to a professional miner near to you to help you with it, you DON'T WANT to lose money setting it all up wrong.
It's not just plug and put it to work, you need to tune things to perfection to avoid every problem possible, such as overheating and degradation of fans. Undervolting the cards is recommended as well as limiting maximum percentage usage.
It's really complicated and it's important to pay attention to in-depth guides and consult an experienced miner that can show you it right and how successfuly he's been running it, especially if he's been running it for a long time.
Don't ever be afraid or ashamed of asking for advice from knowledgeable people on the subject. Don't cheap out on components under any circumstance. Buy things that are certified high quality and can handle the pressure.
In short, read in-depth guides and ask for advices from a very experienced and professional miner near to you or you can even ask for direct help to set it all up and tune it all to perfection for maximum longevity and proficability and stability, as doing it through messages is not gonna be really helpful.
If you want to really get into it, you DON'T WANT anything going wrong and possibly losing parts of your system.