Welcome.
Its in the Global > Style menu page that you will find the drop down selector.
Additionally Korg do great video tutorials on the functions and features of their keyboards.
Going back to chords I do suggest that you try to get used to three fingering chords, it is not as difficult as it may seem.
With your Korg for playing minor chords you have to play using two fingers and seventh chords require three fingers so you might as well learn the correct chord notes.
Eg
Play a C major C, E & G using fingers 1, 3 & 5, notice the number of unplayed notes between each of your fingers. This spacing is exactly the same for all major chords.
For minor chords move the middle finger one note left so C minor is C, Eb and G and again notice the unplayed notes and again this spacing is the same for all minor chords.
Hence learning chords is all about muscle memory.
BTW
The 600 is now an older model that has not had any update for 15 months and I do not think that there will be any more as the 600 was essential superseded by the 700 which is a leap in cost but also a leap in functions and support. Initially I looked to buy a 600 but when I went into my local store they had the newly released 700 on demo, I bought it, one of the first in the UK which they should not have sold as it was many weeks before they got another in stock.