how can i use my proxy??

i mean i try to making a tools but this tools i want to use my proxy inside.

any one have the source ???

i use this source =
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

    End Sub
but error

please give me the correct source and tell me how can i use my proxy on in tools

my english bad i cant explan but help if you can

how to change internet explorar proxy by