Issue with the KNIME explorer


I'm requesting your help as a new user of KNIME. I've just downloaded it and when i start KNIME, i cant see the "KNIMe explorer" window on the top left-hand corner. I've dowloaded the extensions and i still dont have it. How is that possible ? and how can i fix it ? 

Thanks for the coming help

Do you see it if you open View->KNIME Explorer from the menu?