Thanks for playing for ten minutes and for writing this up.
The movement rule is that each knight rides along whichever axis it is furthest from the banner on, and it locks to that line once it starts. Hovering a tile before you click is meant to show every knight's track, but if that didn't come across in ten minutes then it isn't readable enough yet. We've logged it for the next update along with your note about the fonts and styling, which is fair.