There are 3 steam selection buttons on the steam generator: for high, moderate & low steam. The default setting is moderate steam. If you wish to select a different steam setting, press and hold the steam button for about one second until it flashes.
When the appliance is ready for steam ironing at the selected setting, the light in the active steam selection button stops flashing and stays on. Make sure that the temperature control dial is set to a temperature above 2 dots for steam ironing (see chapter 'Using the iron' in the user manual for more details).