How to make a user control

[grupos]

I want to know how to make a web user control with pagelet, since they make
the controls of asp.net
<asp:CheckBoxList ID="CheckBoxList1" runat="server">

<asp:ListItem>asd</asp:ListItem>

<asp:ListItem>asd</asp:ListItem>

<asp:ListItem>asd</asp:ListItem>

<asp:ListItem>asd</asp:ListItem>

<asp:ListItem>asd</asp:ListItem>

</asp:CheckBoxList>