There is a very clear step from here

Install jekyll-import

sudo gem install jekyll-import

Export Blogger content

• login to blogger.com

• click Settings -> Other -> Export Blog -> Download Blog

Import using jekyll-import

Go to the directory where your site clone is stored, run the following:

ruby -rubygems -e 'require "jekyll-import";
JekyllImport::Importers::Blogger.run({
        "source"                => "/Users/swang/Downloads/blog-12-31-2014.xml",
        "no-blogger-info"       => false,
        "replace-internal-link" => false,
        })'

Note the "source" bit has to be absolute path

That's it!