How is frozen data accessed in splunk?

I've been looking at sizing a splunk instance based on https://splunk-sizing.appspot.com/#v=10 and it mentions hot, cold and frozen data. If you want to access the frozen data for some reason what do you need to do ![This refers to the frozen data that im asking about][1] [1]: /storage/temp/107192-splunk-data-retentin.png