Temperature Controlled Fan Controller

I was wondering if you guys could help me out. I'm a novice when it comes to this stuff.

I need to install some fans in my PC cabinet badly. There isn't any airflow in there and my PC gets way too hot. Yes, I could always just take it out of the cabinet, but for space reasons it needs to stay. Ideally, I would like to make them automatically turn on and off, as well as adjust their speed based on the internal temp of the cabinet. I have found similar projects, but they are old and I am afraid I am going to run into problems trying to work around old code and such. I figured it would be better to come in here and ask and possibly start from scratch to avoid that. You can see what I'd like to do here.

https://www.barnesian.com/arduino-powered-smart-fan-controller/

Another option would be to just forget about the temperature controlled aspect, and have a simple on/off with speed control. I'd imagine I wouldn't even need an Arduino for that? If so, this route would probably save me a considerable amount of money on this project.

I'm looking to use just PC case fans. Along the lines of two of these: 250mm Silent Case Fan They require 11w per fan.

Can you guys offer some help? Like I said, I'm a novice with very basic knowledge. I'd appreciate it greatly.

If you were to power the fans from the PC power suppy, then they'd automatically come on as soon as the PC is fired up. I'm not sure there's any value in controlling the speed.

It's not such an interesting project but it's probably the most practical solution to the problem.

this might be relevant:
PWM controlled PC FANS

You need to add the temp sensors (DS18B20 or other) to obtain the temp information for the conditional statement that determines the PWM speed.