this is a major major problem for me...i could fail my module if i dont implement this in my system!!

i've downloaded some examples from this site but i could not understand whats it doing..and how to implement it in my forms..im hoping some one out there can help me out here...it'll be one reall really appreciated help.

anyways this is my situation, i have frmQueue which has a datagrid showing only one column (ACCT ID) and another form named frmDiagnosis which has got a textbox called txtACCTID. the user clicks on the first cell in the datagrid in frmQueue and it gets loaded in the textbox in frmDiagnosis.

pls some one help me here. im new to C# so the examples really make me feel blur...