Just a few months ago I would have said A/B testing on Adsense was a pretty complicated process, but thanks to recent changes it has got a lot easier.
These days A/B testing is called "Experiments" and it is found in the Optimisation tab. Any opportunities you have for some "A/B" testing are located here...
As you can see, in my own account I have 3 possible experiments. they are: "Ad unit Settings","Allow & block ads" and "Ad Balance". By clicking on one of these will open up the "experiment" settings.
The first thing to do is to call your Ad experiments something. In this case, maybe "Ad Balance 24,08,2018".
Then just under the experiment name, you can see the current setting (A) and underneath that the possible experiment settings (B). You Adjust the experiment settings to the point you are happy and click "Create".
Before you do that make sure you are happy for Adsense to "Automatically choose Winner" this means they will permanently implement the changes if the revenue amount is unchanged or increased during the experiment. While it is easier to let Adsense do this sometimes you just want to test and not implement. If this is the case do make sure you move the slider to the left (unmarked).
Once you click create Adsense will text your experiment for 30 days and then pick a winner. It really is as easy as that and just about anyone can do it.
Thank you for taking the time to read this post and if you have any Adsense questions do let me know in the comments below.