1) To add Bing search to your website click here or go to Bing searchbox page.
2) You can access two types of search options. a) Basic SearchBox, b) Advanced SearchBox.
A basic search box is the one with which it displays the search results in the Bing website. A Advanced search box is the one in which the results are sh0wn on your own website.
3) After selecting any of the one, you will have to enter the sites through which you want the engine to search.
4) The next part is the formatting part, i.e., to customise the look and size of your search engine tool.
5) You will get the code for this. You can copy it and paste it in your blog's template.