Making a Square

In the toolbar at the leftside of your screen you can see a rectangular looking button. Click on the button.

Now click and hold on your image and drag out a square. To have a perfect square, you need to hold down the Shift key, then click and hold on your image and drag out a square. When you have the size you like, let go the mouse button.

Not pressing the Shift key

Pressing the Shift key, then you have perfect square.

Now we need to add colors the square. Look for the Swatches pallet on the screen, go over to it with the mouse and select a color,  I choose blue ( if you don't see the swatches, then go to Window>Show Swatches.

Click on the Paint Bucket

in the tool bar on the left.

Now click inside the square you made to fill it in with color.

Then finally hold down Ctrl + D to deselect.

Making a Circle

You should see a rectangular looking icon in the toolbar. Hold the mouse button down on this, you will see another sub-tool bar pop out. Drag over to the Circular Marquee and let go of the mouse. If you want to make a circle, then just click on the Elliptical Marquee instead.

Now click and hold on your image and drag out a circle. To have a perfect circle, you need to hold down the Shift key, then click and hold on your image and drag out a circle. When you have the size you like, let go the mouse button.

Not pressing the Shift key

Pressing the Shift key, then you have perfect circle.

Now we need to add colors the Circle. Look for the Swatches pallet on the screen, go over to it with the mouse and select a color,  I choose blue ( if you don't see the swatches, then go to Window>Show Swatches.

Click on the Paint Bucket

in the tool bar on the left.

Now click inside the circle you made to fill it in with color.

Then finally hold down Ctrl + D to deselect.