I can’t tell you what to set, since it depends on the theme, but those are probably custom fields.
If the fields aren’t hidden you can see them just by checking ‘custom fields’ in the post editor.
Often the fields are hidden (WordPress won’t show them if they start with an underscore “_”). If so here are some ways to find the field names:
– Ask the theme author
– View the web page source in the post editor and try to find them there
– Use a plugin – some plugins are available that can display hidden custom fields
– Check your database tables. Custom fields are stored in the ‘postmeta’ table.
I hope that helps.