How to add new columns on Transportation proposal Screen of NWBC

Dear TM Experts,

Please help me how can we add Z columns on Transportation proposal Screen of NWBC. I have a requirement to add 2 columns and populate these columns with Maximum Capacity os TEU and Remaining Capacity of TEU of the carrier.

Can one help me steps that need to be followed to add 2 new columns and build logic for these columns at Transportation proposal Screen of NWBC.

Thanks in advance.

Regards,

Md.Rafi