I'm trying to install the Flutter plugin, but am having problems with Step 2, which says
"CHMOD 777 'cache', 'files_flutter', 'modules' and 'purifier_lib/HTMLPurifier/DefinitationCache/Serializer/HTML' folders under '/wp-content/plugins/Flutter'. You should be all set."
What's the mean? And, more importantly, how do I CHMOD 777 those files?