You have two basic options, depending on how you want your hanging indent to look.

Using a pre-defined style:
1. Open the Format Stylist (select: Format -> Stylist from the pulldown menu)
2. Have the text cursor in the text that you want to format as hanging indent (or have the cursor in an empty text style and enter the text later)
3. Double-click on the "Hanging indent" choice in the Stylist window. This default style has a hanging indent - but it also has a left margin offset of .19 inches.
Create your own style:
1. Open the Stylist (as described above)
2. Select one of the "generic" styles such as "Standard"
3. Right click (in the Stylist window) to get the context menu and select "New ..."
4. In the dialog that appears, enter a new name for the style
5. Click on the "Indents & Spacing" tab. For a .25 inch hanging style, you would enter ".25" in the "Indent From left" field. Then enter "-.25" in the "Indent First line" field
6. Click on "OK". The new style will be available in the Stylist list.