Sub Menu in ASP.NET

Question

Sir. I just created a Menu. Now I want to make this standard by adding sub menu to this.

here is the code I used to implement Menu:-

<asp:Menu ID="NavigationMenu" runat="server" EnableViewState="false" Orientation="Horizontal"   StaticDisplayLevels="2" BackColor="LightBlue" ForeColor="Black" StaticSubMenuIndent="10px">
 <StaticSelectedStyle BackColor="#DE0031" />
                        <StaticMenuItemStyle HorizontalPadding="15px" VerticalPadding="5px" BorderStyle="NotSet"
                            BorderWidth="1px" BorderColor="white" />
                        <DynamicMenuStyle BackColor="#E8E8E8"  />
                        <DynamicSelectedStyle BackColor="#DE0031" />
                        <DynamicMenuItemStyle HorizontalPadding="5px" VerticalPadding="2px" />
                        <DynamicHoverStyle BackColor="#DE0031" Font-Bold="False" ForeColor="White" />
                        <StaticHoverStyle BackColor="#DE0031" Font-Bold="False" ForeColor="White" />

<Items>
        <asp:MenuItem Text="Home" NavigateUrl="~/MainWindow.aspx"  />
 <asp:MenuItem Text="School" NavigateUrl="~/SchoolCreation.aspx" />
       
        <asp:MenuItem Text="General" NavigateUrl="~/Class.aspx" />
        <asp:MenuItem Text="Role" NavigateUrl="~/Role.aspx"/>
        <asp:MenuItem Text="Subject" NavigateUrl="~/SubjectMaster.aspx" />
        <asp:MenuItem Text="Student" NavigateUrl="~/studentCreation.aspx" />
        <asp:MenuItem Text="Teacher" NavigateUrl="~/TeacherCreation.aspx" />
        <asp:MenuItem Text="Mark" NavigateUrl="~/MarkEntry.aspx" />
        <asp:MenuItem Text="Reports" NavigateUrl="~/StudentReport.aspx"/>
      
    </Items>
</asp:Menu>

And the output is:-



I want your help to improvise this menu to look like this:-


please find a solution.