This excerpt of the New Application Extension dialog shows a total of five fields: two in the first row, two in the second, and the fifth field, which occupies the entire width of the dialog. The first row contains Extension Name and Extension ID. When you type in a name, that name also appears in the ID field, pre-pended with the word site. The next row shows Workspace Name and Development Environment. The latter is usually set to "Development", but you can enter a workspace name of your choosing. The next field takes up the whole row: Base Oracle Cloud Application. This field is shown with its drop-down list displayed, which contains many entries in the form App UI name (from extension name). The first entry in this drop-down list is None.