Import wizard sql 2014

I am trying to import an excel worksheet into an existing table - after I select the source file I get a message 'connect string property not initialized'. I googled and I see it requires a code to initialize that I don't follow - it seems to be 'c++' code. Is there a way to graphically initialize the connect string property or simpler way so I could import my table from the excel sheet

Did you set the Data Source type to Microsoft Excel?