Subform Automatically Add New Record And Save It With Default Settings

I Have a main form called table one has 3 fields an autonumber as primary key and i have a subform called table 2 has 3 fields one an autonumber a primary key , second is an integer which is equal to table 1 primary key, and third is a text with default value set to N/A

i want when the user enter info in the main form and save it, the subform automatially add new record and save it with default settings..so far what s happening , that the related field in the subform to the main, is getting change but record is not getting save in the table 2