How to add numeric page numbers in simple catch theme?

Hi , For adding Page Numbers in Blog Post , I have installed a plugin named WP-PageNavi. http://wordpress.org/plugins/wp-pagenavi/installation/. But as instructed there , I am unable to find the same in simple catch theme code. Kindly help me out . Here is my site: www.techriff.com . I want to replace the "Older post" in home page . And want to add numeric page navigation to index and archive page template. If you do have any other solution for adding page numbers to blog post site, then kindly quote here.