playback on Kawai ES6?

Hello,

I got a digital piano (Kawai ES6). I know, it's very old, but it's still very good for me. I also found the manual for the digital piano, but I didn't find anything there that answered my question.

I have a piece of music ("A Million Dreams" by The Greatest Showman) that I'm currently playing. Now I'd like to have the melody in the background. I have the matching playback melody for my sheet music.

Is it possible to load this melody onto the digital piano and then play it from there while playing it yourself at the same time?
If it is possible, is it also possible to vary the playback speed and rewind/fast forward?