Brain’s Cache for pages is currently limited to a file based caching. This will be expanded upon at a later date, but for now you can set up caching by finding and editing the cache_cfg element in config/core.php. Configuring the cache is all that is required to use it.
'cache_cfg' => [ // Cache /test.xml for one min '/test.xml' => [ 'mins' => 1, 'mime' => 'text/xml' ], // Cache /foo/bar for 10 minutes '/foo/bar' => [ 'mins' => 10 // 'mime' defaults to 'text/html' ] ],