[Plugin: W3TC Total Cache] Location of config file to add redirects

I am importing files in media library using w3tc. at the bottom of the import page it says

Add the following directives to your .htaccess file or if there are several hundred they should be added directly to your configuration file:

Since I’ll have several hundred redirects, I want to know which CONFIG FILE (not htaccess) i am supposed to add the directives?