Use the native date format in DataGraph yyyy:mm:dd.
For example, enter in the include box: 2020:01:01, 2020:01:20
You also could use variables. The following shows using a Number from column variable to pull the min and max, so you don’t need to type the numbers.
Note that in case you want to stack these, you can use the Split Y-Axis and the stacked graphs will share the same x-axis.