How to Sync User's Profile Custom Fields

Hi, I have got your excellent MailChimp User Sync plugin to sync my site Authors to my MailChimp list…. so far, so good!

But, I need some help in how to pull across some custom content from the User’s Profile page.

I’m using Remi Corson’s ‘Custom User Contact Methods’ plugin (http://www.wpexplorer.com/wordpress-user-contact-fields/) to create custom user fields i.e. Company Name, City/Town, Phone Number.

I’ve looked at the ‘Send additional fields to MailChimp’ and I’m assuming that this will pull across those custom fields, unfortunately, I’m a bit useless at coding. Could you please give me a bit more info on how to use the mailchimp_sync_user_data filter.

01: Remi’s code contains this…array( ‘company’, __(‘Company Name’, ‘rc_cucm’), true ), to create the fields on the user profile page. And my merge tag value Mailchimp is COMPANY.

I’m assuming that I would edit the mailchimp_sync_user_data filter like this???
$data[‘COMPANY’] = $user->company;

02: What file (and the place within the file) do I put the mailchimp_sync_user_data filter once I have edited it?

Many thanks for your time & knowledge.

https://wordpress.org/plugins/mailchimp-sync/