I'm having trouble with one of the trailhead modules, Lightning Components Basics Input Data Using Forms https://developer.salesforce.com/trailhead/lex_dev_lc_basics/lex_dev_lc_basics_forms. 

In a previous module I set up the SLDS static resource and now in this module I'm asked to acess it and I'm not getting the custom styling that is supposed to be implimented. I copy-pasted the code exactly as it is shown in the module and only changed the name of the static resource.

expensesApp.app

<aura:application>
 
    <!-- Include the SLDS static resource (adjust to match package version) -->
    <ltng:require styles="{!$Resource.SLDS201 +
         '/assets/styles/salesforce-lightning-design-system-ltng.css'}"/>
 
    <!-- Add the "scoping" element to activate SLDS on components
         that we add inside it. -->
    <div class="slds">
       
        <!-- This component is the real "app" -->
        <c:expenses/>
       
    </div>
    <!-- / SLDS SCOPING DIV -->
 
</aura:application>

expenses.cmp

<aura:component>

    <!-- PAGE HEADER -->
    <div class="slds-page-header" role="banner">
      <div class="slds-grid">
        <div class="slds-col">
          <p class="slds-text-heading--label">Expenses</p>
          <h1 class="slds-text-heading--medium">My Expenses</h1>
        </div>
      </div>
    </div>
    <!-- / PAGE HEADER -->

    <!-- NEW EXPENSE FORM -->
    <div class="slds-col slds-col--padded slds-p-top--large">


        <!-- [[ expense form goes here ]] -->


    </div>
    <!-- / NEW EXPENSE FORM -->

</aura:component>

I've tried uninstalling and re-uploading the resource as well as changing the filepath but I can't seem to figure out how to acces this file.
Any help would be really appreciated.