Installing and changing themes
Now that you've chosen the theme you want to use, you'll need to install it into your WordPress website.
You'll have the following two choices, as you did when adding new plugins:
If the theme you want is in the WordPress theme directory, and if your server is set up properly, you can add the theme directly from within the WP Admin
If either of those two conditions are not met, you'll have to download, extract, and then upload the theme by hand
Adding a theme within the WP Admin
As mentioned in the preceding section, you can add a theme directly from within your WP Admin if you've chosen a theme from the WordPress theme directory, if you're using a current-enough version of WordPress, and if your server settings allow. First, navigate to Appearance, and then click on the Install Themes tab, as shown in the following screenshot:
This will look similar to the Add New Plugins page because you have some subnavigation links at the top, namely Search, Upload, Featured...