To group your data by something (date, location, any info you have in your database) you just need to use a Summarize step. 

For example, if you want to count all your customers and group them by the month they signed up, you would add a summarize step with the metric = count of customers and the dimension = month they signed up. The metric is what you want to know about the data, and the dimension is the way you want to group or break down that info.