You have chosen the blogger template. Blogger is a very popular blogging platform that is run by Google. To attract more visitors, and to theme your blogspot page, follow the instructions fo this blogger template as shown below.
Step 1: Select the code in the box below, and copy it (right click and copy)
Step 2: Login to your blogger account and go to Manage "Layout" from the blogger dashboard
Step 3: Click on the "Edit HTML" tab
Step 4: Delete all the code already in the "Edit Template" box and paste the new code in (right click, paste)
Step 5: Click on "Save Template" and you're done!