How to add subscribe button in Video Player

i want to place a button by the button right of video html payer

here is my makeup

<asp:FormView ID="ExpImg" runat="server" Width="100%">
     <ItemTemplate>
           <!-- Video files -->
           <video  controls poster=""   style="width:100%; background-color:#808080"  autoplay="autoplay"  >
                    <!-- Video files -->
                    <source src="<%# Eval("Path") %>" type="video/mp4" >
                    <source src="<%# Eval("Path") %>" type="video/webm">
                    <!-- Captions are optional -->
                    <!-- Text track file -->
                    <track kind="captions" label="English captions" src="/path/to/captions.vtt" srclang="en" default>
                    <!-- Fallback for browsers that don't support the <video> element -->
                    <!--  <a href="https://cdn.selz.com/plyr/1.5/View_From_A_Blue_Moon_Trailer-HD.mp4">Download</a>-->
            </video>
            <asp:Label ID="Label2" runat="server" Text='<%# Eval("VideoName") %>'  Font-Bold="True " ForeColor="White" /> 
            <div id="transcript"></div>
     </ItemTemplate>
</asp:FormView>