How can I upload my code from my local machine to Bitbucket using Tortoise Hg? Can somebody provide step-by-step procedure? I would really appreciate your help.
Did you read Bitbucket's documentation?
They have an extensive "Bitbucket 101" tutorial which explains all the basics step by step.
Quotes from the link:
If you are new to hosting your code, code management with distributed version control systems (DVCS), or either Git or Mercurial, this Bitbucket 101 tutorial gives you a taste all of them. In this tutorial, you'll first install both Git and Mercurial for your operating system. You'll do some work using both Git and then Mercurial. Throughout, you'll use the hosted code management system that is Bitbucket.
[...]
How to work through the tutorial
If you are totally new to DVCS and/or Bitbucket, you should work through each page sequentially as each new page builds on the material from the previous pages At the end of each page is a Next heading that navigates to the consequent page. If you get lost you can use the navigation bar (to your left) to locate the next page. If you feel confident skipping pages or just going to the pages you need, feel free to do that too.
If you are a total beginner you should allow at least a couple of hours to work through the entire tutorial. If you are experienced or just skimming pages, much of this will be familiar to you and it should not take too long.