When using the SOL-VIEW command on a blank PS layout which sub command should be issued first-and why?

The SOLVIEW command creates floating viewports and automates the creation of the correct viewpoint orientations for a TOP, FRONT, and RIGHT SIDE view in the viewports. This command also creates a series of viewport layers for the Hidden and Dimension lines.

When you Enter the SOLVIEW command The next Step is select the UCS putting "U" as Sub Command.