How to combine to shapes into one? Sketch

I have just installed sketch and I am trying to create a circle with a tick sign inside. The issue is that whenever I use the Union option to merge the circle and tick sign the tick sign is hidden. Here are the steps.

1. Insert -> Shape -> Oval
2. Insert -> Vector
3. I draw the tick sign
4. Select all layers specified above and click on union.
5. Tick sign is no longer shown inside the circle.

The union creates a newer shape with the outer boundaries of the elements. In your case, the check mark is inside the circle and the result is just the circle. The right operation would be: 1 convert the check mark into an outline (Shift + Cmd + O) 2 select the circle and the checkmark 3 use the option subtract so the new shape would be the circle minus the checkmark.