Extractor checker

Helo Friends,

I want to check whether there exists any data for the data source 2LIS_11_VAHDR. So i used RSA3 Tcode for checking. But when i execute it i am getting error as " Data source 2LIS_11_VAHDR is not defined in the source system "

Also If any oneof you have documents relating to " Step by step Lo Data extraction " Please share it with me.

Thank you all.