'Show' tick marks: Make it (the column) visible in the library grid. Not all columns need to show, all the time. (Right-Clicking: Hide in the column header, removes the Tick).
Fields are the per/title values that are in the column. They ALWAYS are available in the Metadata editor view (Single or Bulk mode).
Custom Column fields are on the Custom Metadata tab.
Custom Column information is displayed in the Book (info) Viewer and the columns shown there is (tick) controlled by: Preferences: Look and Feel: Book tab.
Some Custom columns are shown in the Tag Browser and may be used just like any other 'Tag' feature'
Custom columns can be used in
templates. The name to use will be the name you assigned the fiels at creation.
Hover your Mouse over a column Header to see the EXACT NAME to use in a template.
Have questions about what type to use. Ask!
Give full details on what you wish to accomplish with this field.
Provide sample values of any data you expect to enter. Note any value restrictions you would place on the data.
and wait for all the back seat drivers to chime in
