how to move selected cell data from multiple datagridview to a single datagridview

I am using visual studio 2012 and sql server 2012. I have to move data from 2 selected cells from two data_grid_view(1 from each) to a single another data_grid_view inserting remaining values at same time in the same row of the 3rd data_grid_view. i have used 3 tables for these 3 data_grid_view. First table is student table, second is book table and third is book_loan table where book_id from book table and roll_no from student table  are its foreign keys. And I have to register book_id and roll_no for the book_loan table  as student take book from the library.