The Color wheel is a useful box, as you can choose a color visually. It is split into two parts:
They are two square cursors, one on the wheel, the other on the SL map. To move them, click on and bring them where you want, or simply click anywhere inside the wheel or the SL map. Note you can cancel a move by pressing the "Esc" key while dragging.
Note that the main colored sample in the Info box will reflect the changes in real-time when you drag one of the square cursors.
Take care: when the current color is a grey (the SL map cursor is then on the left), the hue cursor can not be moved (its border color turns to gray rather than black). This is because a gray color has no hue: change first the saturation, then you will be able to choose the hue.
If inside the Harmony box, you have asked for the "see harmony on color wheel", one or more round cursors will be displayed on the color wheel: they represent the hue(s) and/or the SL values of the corresponding colors in the harmony.
For some harmonies (triadic, tetradic, shade), one of the harmony cursor is active (black border instead of gray): this means yu can move it (only by cliking on it and dragging it) to change the harmony parameter: