...
Running the challenge itself is not all that
different from running a combat encounter (see Chapter
3). You describe the environment, listen to the
players’ responses, let them make their skill checks,
and narrate the results.
Roll initiative ... every player character
must make skill checks to contribute to the success
or failure of the encounter. Characters must make a
check on their turn using one of the identified primary
skills (usually with a moderate DC) or they must use
a different skill, if they can come up with a way to
use it to contribute to the challenge (with a hard DC).
A secondary skill can be used only once by a single
character in any given skill challenge.
......
You can also make use of the “DM’s best friend”
rule to reward particularly creative uses of skills (or
penalize the opposite) by giving a character a +2 bonus
or –2 penalty to the check