Real value of ID numeric

Hello everyone
I recently discovered Grocery Crud, I am very interest by the simplicity of this product, I test it before perhaps buy it. I have a configuration like this picture joined. My problem is in the table5 when I want to select the data in a droplist the values of the field ID_table1, 2, 3 have numeric ID, the ID numeric is correct, but I don’t know how retrieve the real value not the numeric ID. Somebody can help me please, I am newbee in coding. Sorry for my poor English