Asssignment of Standard Pur ord to plant

Hi

I have an issue with Default Pur org to PLant

While ASSIGNMENT - Materials Management - Assign Pur org to Plant i couldnt found any entries in the screen it seems to be blank there is no option to make an entry but i want to make an entry since it is required for COnsignment PO to post it i like to make an entry for Default Pur org to Plant

Please help me to solve this issue

Thanks & Regards,

Senthil.