After a lot of searching, i thought to post my issue on stack. The issue that i am getting is regarding to override the Magento checkout/onepage.phtml. I have placed the onepage.phtml in my custom module template like responsive/default/template/mymodule/checkout/onepage.phtml and defined in the layout.xml as bellow:-
<checkout_onepage_index>
<reference name="checkout.onepage">
<action method="setTemplate"><template>checkout\onepage.phtml</template></action>
</reference>
</checkout_onepage_index>
But the layout of the checkout page is not proper like the checkout progress not appearing and the design is break.
Can somebody tell me what wrong i am doing?