I am still a little unsure what I'm doing despite passing Step 2 of the challenge.
Because, when I created my Lightning Page, only the Boat Search and BoatSearchFrom apps are visible to select. And then when I select them, I get an error message on the page as per screenshot.
The overall process I followed was;
Create or populate the FriendswithBoats.app, BoatSearchForm.cmp, BpatSearchResults.cmp, BoatSearch.cmp. Create a Lightning Page ' Friends With Boats' and drop these components in. Create a tab from the new page and finally, create a Lightning App called FriendswithBoats.app. Noting also, that the BoatSearchForm.cmp requires a dropdown menu(Boat Type), Search box and 'New' button.
But! I'm confused about the bundles which were automatically created through the unmanaged installed package. Should there not have been included; BoatSearchApp.app, BoatSearchFormApp.app and BoatSearchResultsApp.app for each of the bundles. Because, I had to create those. However, i noticed that, in the FriendswithBoats.app, the BoatSearch component is wrapped in there?

FriendswithBoats.app
<aura:application extends="force:slds" >
    <lightning:layout >
    <div class="slds-grid slds-gutters">
          <div class="slds-col slds-size_2-of-3">
            <c:BoatSearch/>
          </div>
          <div class="slds-col slds-size_1-of-3">
            <span></span>
          </div>
    </div>
      </lightning:layout>
</aura:application>

BoatSearchFormApp.app
<aura:application >
    <c.BoatSearchForm />
</aura:application>

BoatSearchResultsApp.app
<aura:application >
    <c:BoatSearchResults />
</aura:application>

BoatSearchApp.app
<aura:application >
    <c:BoatSearch />
</aura:application>