Hiya Ray
What is in the custom style button/area is/are some extra styles and can be exchanged for a few other sets of custom styles that can be found on the internet elsewhere.
Most folk want to make sure they don't lose one or more of their custom styles and so transfer it/them to the next button/area on the right called 'Memory load' and then save it/them to their SD Card. If this is what you want to do just nod your head and I'll explain how to do that.
There's not a lot of point in transfering any of the standard styles into the custom style area IMO.
Rog