Hi, I am looking for a guide that I am able to understand. Can anyone help me with a step-by-step guide, screenshots etc?
I have:

-Z390 Phantom Gaming-ITX/ac
-I7 8700k 3,6GHz
-32GB RAM 3200Mhz
-Samsung 970 EVO SSD (2 x - no spinning drives)
-Radeon RX580 GPU
-Scythe Big Shuriken 2 CPU cooler (Conductunat liquid metal thermal paste)
-Louqe Ghost S1 case
-Corsair SF600W PSU
-2 x Noctua 12X15 in top to force air from sides to CPU and to GPU

Here is what I want:
-A quiet as possible setup
-4.5Ghz OC
-I will be using the setup for light work but it is ok that the fans blow when I need the power (4.5Ghz OC)

I saw some videos from Optimum Tech about undervolting to get a cooler CPU. But I do not understand where I set this up in BIOS. Are there any simple steps to e.g. set undervolt to 1.15V?

My questions are then:
- How do I get the fans to run super quiet when the CPU is not stressed?
- How do I best set an OC of 4.5GHz on my i7 8700k?
- How do I set an undervolt of the CPU that I can control (if I set it too low I understand I will get crashes)