How to add custom Facets and Elements to Sitecore.Analytics.Model.config

Sitecore.Analytics.Model.config.xml

<?xml version="1.0" encoding="utf-8" ?>
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
    <model>
      <elements>
        <element interface="Sitecore.Analytics.Model.Entities.IContactAddresses, Sitecore.Analytics.Model" implementation="Sitecore.Analytics.Model.Generated.ContactAddresses, Sitecore.Analytics.Model"/>
        ...
        <element interface="ISlayTitans.CMS.xDB.Interfaces.Facets.IKeyInteractionsFacet, ISlayTitans.CMS" implementation="ISlayTitans.CMS.xDB.Facets.KeyInteractionsFacet, ISlayTitans.CMS" />

        <element interface="ISlayTitans.CMS.xDB.Interfaces.Elements.ISwatchDownloadedElement, ISlayTitans.CMS" implementation="ISlayTitans.CMS.xDB.Elements.SwatchDownloadedElement, ISlayTitans.CMS" />
        <element interface="ISlayTitans.CMS.xDB.Interfaces.Elements.IVideoPlayedElement, ISlayTitans.CMS" implementation="ISlayTitans.CMS.xDB.Elements.VideoPlayedElement, ISlayTitans.CMS" />
        <element interface="ISlayTitans.CMS.xDB.Interfaces.Elements.ISampleOrderElement, ISlayTitans.CMS" implementation="ISlayTitans.CMS.xDB.Elements.SampleOrderElement, ISlayTitans.CMS" />
      </elements>

      <entities>
        <contact>
          <factory type="Sitecore.Analytics.Data.ContactFactory, Sitecore.Analytics" singleInstance="true" />
          <template type="Sitecore.Analytics.Data.ContactTemplateFactory, Sitecore.Analytics" singleInstance="true" />
          <facets>
            <facet name="Personal" contract="Sitecore.Analytics.Model.Entities.IContactPersonalInfo, Sitecore.Analytics.Model" />
            ...
            <facet name="KeyInteractions" contract="ISlayTitans.CMS.xDB.Interfaces.Facets.IKeyInteractionsFacet, ISlayTitans.CMS" />
          </facets>
        </contact>
      </entities>
    </model>
  </sitecore>
</configuration>