Because Outlook does not natively support CalDAV and CardDAV, syncing calendar and contacts between SmarterMail and Outlook is instead done via settings within the webmail interface.
Sync Calendar
Found at Calendar > three dots > Add to Outlook
After selecting "Add to Outlook", a prompt should appear asking for permission to open Outlook. Then within Outlook is the prompt to add the calendar. Before adding the calendar, "Advanced..." can be used to adjust propagation between devices or change the Folder Name, as in the screenshot below.
After clicking Yes to "Connect this SharePoint Calendar to Outlook", it will be added under "Other Calendars" and updates to the calendar will propagate to the SmarterMail calendar and vice versa.
Sync Contacts
Found at Contacts > three dots > Add to Outlook. The same prompt for permission to access Outlook should appear, along with the same Advanced options.
By default, the new contacts will not be available in the address book when composing a new message. To add the contacts to the address book, within Outlook click People > right click on the newly created address book under "Other Contacts" > select Properties > select the "Outlook Address Book" tab > check "Show this folder as an email Address Book" and click OK.
Afterwards, when opening the address book while composing a new message, the new contacts will be found at the bottom in the "Other Address Books" section.