"Publish Sheet" is no more

The "Publish" feature was intended to prevent volunteers from signing up for slots before the owner had finished setting up the sheet. But unlike craigslist.org (on which the feature was modeled), sheets are never publicly available; the owner has to give the signup link to each volunteer. Thus there is no need to prevent untimely signups, and so publish is no more. The sheet is ready to go as soon as it is created.

You can still close a sheet to prevent volunteers from signing up, and re-open it later if you change your mind.