1. Open a new square document
2. Draw an image in Black and White (Photoshop brushes are in greyscale)
3. Select Edit > Define Brush Preset
4. Name the brush
5. Open Window > Brushes
6. Select your new brush (will appear at the bottom of the list)
7. Select Shape Dynamics to adjust size jitter
8. Select Brush Tip Shape to adjust spacing for fluidity
9. Select Scattering to adjust placement on Axes
10. Select Transfer to adjust pen pressure opacity
11. Save settings