Open modalpopupextender with user control inside

Good morning, I'm venturing into C # programming with webforms, meaning I have virtually no knowledge. My question is this: I have a gridview with 3 columns of clients (name, email, phone), and two buttons (Edit and Remove). I was able to configure for the remove button to delete the record, until ai blz! But the edit button, I want to make a schematic of by clicking on this button in the given record, open a modalpopupextender and within displayed a user control that I created with the editing form, bringing completed the data to edit.

What better way to do this? I'm zero in programming, and I wanted tips. I see a lot on the internet of examples and I get a bit confused if I'm doing the right thing, or I'm traveling.

My edit button, I created it this way:

<asp:Button ID="lnkBtnEditar" runat="server" Text="Editar" CommandName="cmdEditaContato" CommandArgument="<%# ((GridViewRow) Container).RowIndex %>"></asp:Button>

And in the modal part I did the following:

<asp:Button ID="btnShowPopup" runat="server" Style="display: none;" />
    <asp:Panel ID="pnlEdicao" runat="server" Width="400px" Height="150px">
        <uc1:EdicaoContato runat="server" ID="EdicaoContato" />
    </asp:Panel>
    <ajax:ModalPopupExtender ID="ModalPopupExtender1" runat="server" TargetControlID="btnShowPopup" PopupControlID="pnlEdicao"></ajax:ModalPopupExtender>

Passing inside the Panel, my UC EditContact.

My mod even opened with UC, but how do I link this edited record to the form of my UC?