Step 1. Open up your document and select the color you want your dots to be.

Step 2. Open up your Brush (hit “B” on the keyboard) then open your Brush Palette box (hit “F5″ on the keyboard). Select your disired Brush Tip and Spacing.

Step 3. Open up your Tools Palette (hit “U” on the keyboard). Click on the Paths and Ellipse icons to select them.

Step 4. Create a new layer (hit “Shift + Control + N” on the keyboard) and click and drag a circle on to your canvas using the selected Path + Ellipse Tool (hold down the Shift key to keep it a perfect circle).

Step 5. Go to your Paths (click Window > Paths). Click on the little arrow at the top right corner to bring out more path options and then click Stroke Path. Click OK at the dialog box.”