Start by showing the controls and text for only the first step. When
the user completes that step, show the controls for the next step.
Leave the previous steps' controls visible, to let the user go
backward if necessary. Keep it all on one page or dialog box, so
that the user isn't abruptly pushed into a separate "UI space."
In many such step-by-step designs, the choices the user makes at one
step alters the rest of the task (i.e., the task is branched, not
linear). For instance, an online order form asks whether the billing
address is the same as the shipping address. If the user says yes,
the UI doesn't even bother showing entry fields for it.
Otherwise, there's one more step in the process, and the UI shows
the second set of entry fields when appropriate.
This technique is less successful when used to radically change a
preexisting UI, instead of adding UI controls to a blank space.
Restructuring a UI from under a user can turn his sense of space
upside down -- it's very disruptive! But when done in an orderly and
predictable manner, it provides a compact, space-sensitive way to present
a Wizard to a user.
The concept of responsive disclosure isn't new. It was used in 1981 in
the first commercial WIMP interface, the
Its designers considered "progressive disclosure," a more general
concept that includes responsive disclosure, to be a major design
principle: "Progressive disclosure dictates that detail be hidden
from users until they ask or need to see it. Thus, Star not only
provides default settings, it hides settings that users are unlikely
to change until users indicate that they want to change them."
In the Star's Property Sheets, for instance, blank space was
reserved for controls that would appear as needed, in response to
user choices. When a user chose from a set of values including the
word "Other," for instance, an extra text field would appear for the
user to enter a number.
Instructive Interaction: Making Innovative Interfaces Self-Teaching,
by Larry Constantine and Lucy Lockwood, discusses this pattern under the
name "Progressive Disclosure."