Unluckily, a "section" isn't something that has a fixed meaning in web design.
Moreover, how to do whatever you want to do, critically depends on the tools used to make the current contents of the website. If I read your question correctly, the site as it is is designed and made by a designer.
So all I can say: ask the designer to give you the information and tools you need to maintain the site yourself. That should have been in the initial contract, and it's quite unsure if such a request will lead to anything other than a loud laugh and a statement that it's impossible.
I have a new site designed. But i need to know , is it possible for me to add the News section. I have to update my company information like special offers, quotes to my site. How can i add this section? Its not affordable for me to go around the Designers to get this done as per my changes, Hence i would like to get this done self.
Please guide me. what are the details i am supposed to have.?