Step# 1: Need to sign in Google web master tools then you will be the add option on the top of right sidebar.
Step#2: When add the site you need to verify it. Please follow the step under the screenshot. At first you need to download it instruction (1) and upload it on your site document root tree. When upload is finish you need to check it for successfully visiting link see the instruction (3). If it’s okay then click to VERIFY button.
Step#3: Now go to install wordpress plugin http://wordpress.org/extend/plugins/google-sitemap-generator/
When you click the link your sitemap.xml will be automatically generate on your site. Now you need to back your google web master tools for add the name.
N.B. – You can check it on your site for working purpose. www.yoursitename.com/sitemap.xml
Step#4: Now we need to add the name of sitemap.xml in our google web master tools.
Where we’ll write the sitemap.xml file name on your google web master tools?
Click your google web master tools Dashbord then you’ll see the sitemap option on the right sidebar. Just click on it for upload your sitemap.xml file.