A patch is a particular setting of the parameters and their oscillators. A patch can be saved to a file, and then restored from the file later. To open a patch, use File/Open. To save the current patch, use File/Save or File/Save As.
Patches are edited using the parameters dialog. Whorld has various buffers in which patches can be edited. The parameters dialog operates on one of these buffers at a time; see edit selection.
In addition to the parameters and their oscillators, a patch also contains other settings, which may or may not be restored, depending on the patch mode.