You can add a new subsite to your site collection using SharePoint Designer

• Start SharePoint Designer
• Select File ? Open site (choose the site collection you want to open)
• Select File ? New
• On the Dialog box that opens click the tab Web Site
• Click on the link SharePoint Templates on the left and the list of available subsites will populate on the right.

In case the SharePoint Templates don’t show up right away, ensure you enter the correct url in the box “Specify the location of the new Web site“

When creating the subsite you will have to specify the location for the new Web site.

This could be something like: http://litwaredemo/MyNewBlog.

Add a site with SharePoint Designer