Choosing a theme
There’s a small number of themes available for Nesta, which you can find by searching GitHub for “nesta-theme”.
Themes should be installed in the themes folder. They’re normally distributed in Git repositories; the easiest way to install them is to find the URL of the repository (check the theme’s GitHub page) and then ask Nesta to install it for you:
$ nesta theme:install git://github.com/gma/nesta-theme-slate
You’ll need to run the command from within your site’s top level directory. Other than that, you’re done.
Changing between installed themes
There’s also a command for switching between your currently installed themes:
$ nesta theme:enable name-of-theme
The nitty gritty details
Several themes can be installed at once, but only one will be active. The current theme is saved in config.yml.
Set the theme config setting to the name of one of the folders inside the themes folder. In the case of the Slate theme, the folder is called themes/slate, so when slate is the current theme you’ll find this line in config.yml:
theme: slate
If you’re interested in creating your own theme, see how to create a theme.