A number of putative recombinant clones are grown in the small volume of the wells in the 24-wells plate. Plasmids purified from such small cultures are often called minipreps.

The minipreps are digested with EcoRI plus BamHI and run in an agarose gel. This should separate the Lambda inserts from the vector part in the recombinant plasmids... 
Inserts can be identified by size.