datagridview - how to show the selected (form2) DGV rows in (form1) DGV

Hello all,
I am new to this forum and also to vb so pl. excuse me if i do any mistakes...

I am doing a project in window application (VB 2008) where I have 2 forms (form1 & form2) in form1 I place a empty DGV and a button, and in form2 i placed another DGV which i connects to MS access DB, in form2 DGV I add a checkbox column and i need to do is if i click the button in form1 it should show the form2 DGV (till this i got it) and when i checked the rows in form2 DGV the checked rows should shown in form1 DGV. and i also want to add the sum in bottom. pl... pl... guide me.....

Thanks in advance