To change permissions recursively is easy, but if wanting to change only file or folder permissions, it can be do the next way

An example files:

find /path/files -type f -print0 | sudo xargs -0 chmod 0644

An example folders:

find /path/folders -type d -print0 | sudo xargs -0 chmod 0755

WP shows the text wrong, so read change_permissions text.