Are there any user manuals for Zoho features or are we just supposed to figure out how things work from the toolbar menus?

At the moment I'm looking for documentation of Sheet operation, specifically,I need to do a find and replace on a column but I can't find anything as a place to begin to learn how to do this.

On line user manuals in general would be a great help; particularly if the contain info as to how to do stuff from a regular browser and from Safari on my iPod.