How to read the app.config file in C#

I have been stuck on this for a while now. Basically I have an app.config file with multiple layers such as follows:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
  </startup>
  <configSections>
    <section name ="Customer" type="ConfigTest.CustomerConfig"/>
  </configSections>

  <Customer>
    <add key="ID" value="100"/>
    <Addresses>
      <Address>
        <add key="Street" value ="12 Brit Street" />
        <Otherinfo>
          <Random>

            <add key="Randoms" value="ignore this"/>

          </Random>
        </Otherinfo>

      </Address>
    </Addresses>
  </Customer>
</configuration>

I am trying to extract this but I am having issues as the program only returns first layer. I am using this to access the first layer

Any help would be appreciated.