These are the settings I change.
I set -15 not -25 as shown in the screenshot. If you want an easy overclock try -15 it should work. If not go -10.
To stress test use AIDA64.
See the section on stress testing the CPU in this video:
You might as well start -25 and test the cpu with Aida64 each time until you find stability.
Just take off -5 each time you test.
So -30, -25, -20, -15 -10.
Once you find something that is passing Aida64 I would let it run for about 30 mins and you should be good after that.
If you get any instability in a game just lower -5.
For context I ran my cpu at -25 for about 3-4 months and thought it was stable. I started getting blue screens in The Last of Us part 2 and I blamed the game. But in reality it was my under volt.
When I used Aida64 to check it was not passing. Only -15 passes for me and it has been rock solid since.