The available patterns are displayed across a number of pages.
At the bottom of the dialog box are three insertion modifiers.
Size - This is the default size of the repeatable pattern, for example you could enter 225 (mm) if using a brick pattern.
Y Ratio - This allows the pattern to be distorted in both the horizontal and vertical axis.
Angle - This is a rotational angle applied to the pattern.
To select a pattern simple click on the thumbnail picture, set the insertion modifiers as required and click OK.
The prompt reads:
Give Hatch Origin Point:
Indicate an origin point for the hatch pattern using any of the snaps and input options and the hatch patern is added to the drawing.
If multiple boundaries are selected they will be hatched separately. Any boundaries completely contained within another boundary will not be hatch, effectively being 'holes' or 'islands' within the outer boundary. For any boundaries which partially overlap then the intersecting part of the boundaries will not be hatched. The following diagram picture demonstrates this, showing the the resulting hatch when both shapes are selected together.