@gxjansen Is this what you’re looking to set up? 
In this example, 1 User signed up on April 17th, and 3 signed up today, April 21st:
The data setup I used is:
*Note: This is showing the past 30 days and the future 3 days so the graph doesn’t get cut off on April 21st. If you want to remove the next three days, the Ending Date would just be “Current date/time”