Your site is a CCM site which is on a WebBasics plan (This plan does not provide hosted emails on Business Catalyst).
If you want to create email addresses on this site, you would need to setup your email server elsewhere and configure the MX records on your site to point to that external mail server.
If you want to use Business Catalyst's hosted email services you would need to use a WebBasics+ or higher siteplan. To upgrade your CCM free site, Access your site's admin area -> Site Management -> Upgrade Now -> choose the desired site plan and billing frequency -> Add personal and credit card details -> Submit.
Please refer this article about setting up email accounts on your BC site: http://docs.businesscatalyst.com/user-manual#!/site-settings/email-users
For setting up records to point to external mail server, check out http://docs.businesscatalyst.com/user-manual#!/site-settings/email-users/creating-inboxes- for-your-users
Regards,
Surjeet