Peter, first and foremost, I learned to use both the style creator and voice creator when I purchased my PSR-2000 many, many years ago. All of that information was in the user manual. I sat down at the keyboard with that manual at my side and created my first style, which, BTW, was absolutely horrible. I eventually got better at it, but it took months of practice with that feature to get something acceptable. The same holds true with the voice creator, and I have shared several of those voices on this site.
For step by step, I have written several step by step instructions and posted them on this forum. I did one for registrations that has been downloaded many, many times. Fred did a video about the same subject sometime later. I learned those things from the user manuals - not from any other source.
The pioneers on this forum have posted hundreds upon hundreds of instructions showing members how to do things. Keep in mind, though, we learned all this by gleaning through the manuals.
Not only did I do this with several Yamaha Arranger Keyboards that I owned, but I also did it with some I didn't own so I could provide assistance to those on the forum that had those keyboards and were not able to find solutions to their problems. I also poured through the pages of user manuals for the Korg M1, Roland G-800, and a few lesser known boards that I owned. As a working musician, who made his entire income from performing on stage every day of the week, I needed to know how to do these things in order to get the most out of my keyboards, thereby providing my audiences with the best entertainment I could possibly provide. To me, this was one of the most important aspects of being an entertainer/musician/singer. All that information made me one of the most successful entertainers in my area for more than 3 decades. And, the locals around my part of the world frequently called me "The Professor" because I was able to solve their arranger keyboard problems often with just a short telephone call. I thought that moniker was very flattering.
Over the years, I have always strived to provide as much detail as possible when answering questions about a particular problem that a person may have encountered. Most of the time, I no longer have to crack open the user manual to make sure the information I provide is correct, but there are times that I still must do exactly that. As I pointed out earlier, some folks seemed to a bit put off that I would provide them chapter and verse, including the page numbers in the owner's manual. Most, were just happy to have their problem solved.
Keep in mind there are usually two manuals that come with every keyboard, the user manual and the reference manual. Both are kinda intertwined, especially when the problems encountered are a bit complex. Now, if you cannot find it in the manuals, then you have two options - ask the question here, or beat your head against the wall trying to figure it out on your own. I have the lumps to prove how many times I have used option #2.
Good Luck,
Gary