I am using m2m table where I am not able to see needed fields in the reference to table

[SudeepJ]

I am using m2m table with the reference of two tables shipping  case and configuration item table (CI class manager) name LRT platform, however I have designed form and list layout of LRT platform table still that list is not available in m2m reference selection, and How can i select the column whose value I want to take in reference column.

[SudeepJ]

Above is m2m table show form image and below is referenced ci table list layout.