After you upload a new WordPress theme, it won’t change the appearance of your website or blog until you activate it. Activating a new WordPress theme is really simple, and I’ve provided screenshots and instructions for every step of the process. Just follow along, and your new WordPress theme will be activated in a matter of minutes!
Enter your username and password and click “Log In”
Click on “Appearance”
You will see the themes available to you. If you haven’t downloaded additional themes, then you will just have your choice of the 2 themes that come with WordPress, Classic and Default. Your blog will automatically use the WordPress Default theme, but you can preview how your blog would look with the WordPress Classic theme (or any additional themes you download) simply by clicking either the image or name of the theme.
If you don’t like the way the new theme looks, just click the X to close the preview. If you like the new theme, then just click “Activate WordPress Classic” (or whatever the name of your chosen theme) to use it for your blog.
Once you activate the new theme, you will see that it is now listed under Current Theme. If you would like to see how your blog appears to visitors, just click “Visit site”.
And that’s it–you now know how to activate a WordPress theme!