Start with a new document in the dimensions you want.
Ensure Snap is turned on:
View>Snap - Make sure it's ticked!
Drag a new Guideline from the top and it should Snap to the middle of your document. Now go to your shape tool and select the Elliptical shape tool.
While holding down your Shift key, make a circle the size you want, make sure also you have the correct colours selected at the top (see video)
Now drag a new circle out and then drag it to the guideline in the document until it 'Snaps' Centre.
Select the Marquee tool and drag from the bottom up until it intersects the circle and snaps on the centre line. Right click on your circle layer and select Rastersize Layer, with the Marquee still showing half way through the circle, select your eraser tool and remove the lower half. Once this is done, Duplicate this layer (
Ctrl+J) and then drag the newly created layer shape to the side of the first circle you created. Once you have both these circles selected, click
Ctrl+J again then go to:
Click:
Edit>Free Transform>Flip Vertical.
Now space them as you wish, selecting each newly created half circle.
Video attached to illustrate. (note I selected Flip Horizontal instead of flip Vertical lol - Been a long day hehe)
