Create new polygon hotspot: in editor, click Elements tab, click Polygon, press Shift + mouse click to create different points of the polygon; click Save button
Change color, opacity of border and filled area of polygon area: click on the polygon, a tool bar will be display, click Polygon Appearences
Change color, opacity of border and filled area of polygon area on mouse over: click on the polygon, a tool bar will be display, click Interactions, on Hover section select Change Appearence