How can I add menus or buttons through admin?

Hi,
I need to add some buttons/menus on the top and left navigation bar. Can I do it through admin? If not, how to?
Thanks.

open the admin.sitemap
nopcommerceStore/administration/admin.sitemap

Hi, Hezyz, thank you very much for your help. I am sorry that I did not state my question clearly.
What I am trying to do is adding menus/buttons of store front through Admin panel. Such as adding menus at left navigation bar under INFORMATION section. I tried to use Add New under  Home > Content Management > Topics of admin panel. But the topic I added won't show up.
Any advise?
Thanks.

rogertom wrote:
It is not done automaticaly :(. Check:
https://www.nopcommerce.com/Boards/Topic.aspx?TopicID=2230

I have created a new topic. How to add it to top menu for nop 2.1? I couldn’t find HeaderMenu.ascx and sitemap file for the top menu. do I have to change source files?
Please advise. Thanks