A number of readers have been having problems downloading and installing templates from third party creaters and modifiers of New Blogger templates, so here is a post to explain the process.
Before I get to that, let me again repeat the importance of backing up your current template AND Page Elements before you change template. Refer to Backup New Blogger template PLUS Page Element and change template. This post will also show how to get to the template editor window.
Generally, 2 methods are offered. One, the one offered by Stavanger of Blogcrowd, gives the template which you have to copy and paste into the template editor window. For tasks like these, it is best you have a browser like FireFox which has tabbed browsing. Then you can be in the page with the new template in one tab and logged into Blogger in another tab in the same window.
In the box containing the new template, click inside the box, press ctrl+A (or right-click and chose "Select all") to highlight all the template, press ctrl+C (or right-click and chose "copy" to copy the new template into clipboard. Go the the Blogger template editor window, click inside the template editor window, press ctrl+A (or right-click on mouse and chose "Select all"). Press the DELETE key. The template window will now be empty. Click inside the empty template window, press ctrl+V (or right-click and select "Paste" to paste the new template from the clipboard into the empty template window. Preview, and if there is no problem, click "Save template.
In most cases, the template is downloaded and saved as an xml file. In this case, in the template editor, click "Browse" at the top of the page, navigate to where you saved the xml file, select it, click "Upload". When done, click VIEW BLOG to make sure everything is OK.
Any further problem, comment in this post and I may use your comment to make the above clearer.