Gaia Sky offers two different ways to control object visiblity: type visibility and per-object visibility. The main difference is that, while type visibility acts on all objects of a given component type (think stars, labels, grids, planets, etc.), per-object visibility is capable of hiding and showing individual objects.
You can toggle object types on and off by clicking on their icon in the
Type visibility pane in the control panel, as described here.
You can also hide and show individual objects by using the eye icon in the focus panel (when in focus mode) or by using the dedicated window, as described in the individual visibility section.