Show Categories on the top at the place of pages

Hi,

I am developing my blog first time and I really love this theme, but I want to customize my page according to my requirements. I need all the categories on the top of the page where I current have menu for all the pages so that when visitors click on the link, they will land to the category page where they can see all the articles related to that topic.

In addition I need some pages link on my footer where I can put the links of contact me, disclaimer and so on.

Please help me to sort out this problem.