A standard template for organizing structuring tests is given/when/then[3]:
given ... the system is in this particular state
when ... this interesting thing happens
then ... these are the consequences
This structure is readily understood by non-technical business users, and helps them (and the team) focus on the point of the test.
In terms of mechanics, one approach is to put the "given" into the setup page for a test, with the "when" and the "then" in separate pages. Alternatively, as the archetype does (see Chapter 2, Using the FitNesse Archetype), you could separate out the "given", the "when" and the "then" into a hierarchy of pages.
Separating out the "given" from the rest of the test makes it easy to include that given in other tests (discussed further in Section 3.6, “Factor out common "Given"s”), and it also allows us to run up the viewer to inspect the setup (see Section 3.5, “Using the RunViewer fixture”).
Separating out the "then" from the "when" makes it easy to identify the individual post conditions. A new requirement might mean only the addition of a new post condition. A downside is that the "given" and "when" will be run for each post-condition, leading to longer test turn-around times.