Once the application is installed you can use the Preferences dialog accessed from menu Options > Preferences to customize the application.

You can always revert modifications to their default values by pressing the Restore Defaults button, available in each preferences page.

If you don't know how to use a specific preference that is available in any Preferences panel or what effect it will have you can open a help page about the current panel at any time pressing the help button located in the left bottom corner of the dialog or pressing the F1 key.

A restricted version of the Preferences dialog is available at any time in the editors of the Oxygen XML Author plugin plugin by right-clicking in the editor panel and selecting Preferences:

Eclipse Preferences dialog - restricted version