Undervolting i7 8700 with Asus Z370-i mobo

[Fatalution]

Basically, I have i7 8700 sitting inside mini ITX case. It gets pretty hot (non-delidded), can hit up to 85C occasionally.

I want to undervolt it. And have no idea how

I've spent two days searching for a guide based on Asus BIOS and found nothing. Main concerns I have are:

1) How can I just lower my voltage in BIOS if my voltage there is shown as 0.992, which is obviously lower than CPU usually consumes (it runs at 3.2GHz at BIOS, but at 3.8-4.2 in Windows)
2) How do I lower the voltage in BIOS? What and where should I choose and click?
3) How do I use offset and what is it for?
4) What is adaptive mode?

5) I want to save my Turbo mode (I've seen many guides locking the clocks to high amounts, turning Turbo Boost off)

I need someone to write a guide for me... Please

Specs:
Asus Z370-i 
i7 8700

[TheKDub]

Check this out ^

 

You'll just want to drop the frequency and voltage, rather than increase it.

[Fatalution]

40 minutes ago, TheKDub said:

Check this out ^

 

You'll just want to drop the frequency and voltage, rather than increase it.

His guide is useless for me, as he locks the voltage and frequency manually, as well as I don't know how he got the number he input into the cpu voltage. He didn't increase anything, he just hardcoded the numbers 

 

So, I'm still in the blue regarding the undervolting