In Custom Reports, selecting a dataset allows you to pull information from that dataset.
You will need to select the dataset prior to viewing your reports else no data will present

Steps to Select a Dataset in Custom Reports:

1. Press '+ New Report' :
   
   
   
   

2. Select a dataset:
   
   
   
   
   
   

3. Add Data Source To Report:
   
   From here you are able to either drag and drop the information you want into a table or add it to a chart.
   
   Examples:
   Table
   Chart