Assuming that you have implemented the modification suggestion to your existing code problems as said here :
http://www.codeproject.com/Answers/102443/newbie-navigation-problems.aspx#answer1[
^]
Modify the code for Diary.aspx as follows:
<%@ Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="Diary.aspx.cs" Inherits="Diary" Title="Untitled Page" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="body" Runat="Server">
<asp:Calendar ID="Calendar1" runat="server"></asp:Calendar>
</asp:Content>
This should show you a nice calendar in the browser :)
By the way, randomly writing codes and trying different things is not the correct idea of learning programming and doing things. You need to try to understand first what you are trying to do and learn how to do those with the programming platform/tool you are going to use. Google is your best friend.
Best of luck :)