Hi @foysal,
Since that is not an official theme (an dI guess that is a paid one) you will need to request support to the creator/seller.
It's a little bit hard to help you because no everybody knows the code of that theme.
Normally, with Magento and default themes you can use something like this:
{{block type="catalog/product_new" column_count="6" products_count="12" name="home.catalog.product.new" alias="product_homepage" template="catalog/product/list.phtml"}}Where column_count is the quantity of columns and products_count is the total quantity of products.
