The first step is to start with a normalized data model.
Create an entity in your domain model for example called “Measurement” with attributes:
Now you create some objects of entity Mesaurement to represent the data you want to display.
Then use MeasurementDat as x-axis end MeasuredValue as y-axis for your graph.
Does this help?
Did you check out these resources already?
If so, what exactly is the issue you are facing?