I think that most arrangers that do not have a touch screen all have similar navigation..
1.You press a button
2. Look in the screen
3.The styles & or sounds are lined up next to function buttons on each side of the screen
4.You touch a function button to select what you want ..

How many pages are under each sound & style button are a factor and this is where Yamaha products become a problem. There are many pages under the sound & style categorys , making it hard to navigate in real time.. Ketron is never more than 3 pages with sound selection.. or style selection.