Never used it, but here is my explanation.

Let's say you need to provide access to a particular area in your application based on the number of years of experience.

So Manager's need 5 Years of experience to access that feature in application while User's will need 8 Years of Experience to access that feature.

Now a Manager has below Access Role

App:Manager

And User have following AccessRole

App:User

And Admin has following Access Roles

App:User

App:Manager

So in this case, you will create a Rule-Access-Setting "Experience"  and specify in both access roles.

So now at runtime, you can use function getSetting(AppliesTo, SettingName) to get the setting value for logged in operator and control application behavior access.

Also, notice that Multiple settings behavior will be useful for Admin which have both access roles with different settings for Experience, so the largest Experience will be picked, 8 in this case.

I know that this example doesn't makes much sense since i just went through the help but should be enough to understand the basics

Also Sort function can be used if Data type is string and you want to sort based on Card Type (Platinum > Gold > Silver)

Let me know if this helps.