Unless you are a plugin or theme author you are not supposed to do any coding. However, WordPress is an open source software and nothing stops you from tweaking it the way you like.
If your theme has a menu bar, you'll get the menu bar. There are thousands of WordPress theme. Just choose the one that fits your needs.
Do you have your own WordPress blog already? Administration Panels is what wordpress developers call the admin interface of your blog. You enter Administration Panels every time you log in. Administration panels (located at http://your-wordpress-url/wp-admin/) are where you control the behind-the-scenes operations of a site. Here is the most comprehensive information about WordPress Administration Panels: http://codex.wordpress.org/Administration_Panels
i don't have wordpress blog but i am buying hosting .After buying i want to start wordpress blog.so to make postings i have to go to admin panels.how can i access the admin panel?do i need wordpress.com account o access admin panel?
If you are getting your own hosting, you do not need anything from wordpress.com. When you get your own host, go to wordpress.org and download the latest install build. Upload to your webhost and install via the instructions provided in the download.
If you go self-hosted (otherwise you don't need to buy hosting), you don't need a wordpress.com account. However, you might need a wordpress.com account to get a key to activate Akismet plugin to fight comment spam. And having a wordpress.com account may help you to get accustomed to wordpress (wordpress.com admin panels are almost the same as in your future self-hosted blog). If you want to know more about Administration Panels, just read WordPress docs. Here are some more useful links: Getting Started with WordPress First Steps With WordPress
after installing wordpress blog script and uploading theme can i start posting frequently?do i have to do any other thing in order to do regular postings?