Just mention some variant of
in your commit message, and Kiln will automatically associate it with the corresponding case in FogBugz. These forms are all completely identical, as far as Kiln is concerned; just choose whichever one gives you the best readability. The commits will appear inline in FogBugz in the associated cases, and links to FogBugz will appear under the "Cases" button when viewing the changeset in Kiln.
If the bug you mention is a review, then your changeset will automatically be added to the review whenever possible (i.e., it's in a related repository). Cases associated with changesets in a review are also associated with any reviews that changeset is in automatically. You can see them from the "Cases" list when viewing a review.
If you forget to link a changeset to a case or review at at commit time, Kiln allows you to associate cases with changesets after the fact. Simply click on the "Add Case" button when viewing the changeset you've just pushed, type in the case number, and you'll be good to go.
Note: here is the regex we use to parse commit messages for case numbers.