Which widget are you currently using to display the chart? There are multiple possible solutions. You could build a json for the anychart widget using export mappings. With this approach you have more freedom to eg add extra lines or labels within the chart.
if you want to display multiple series in a line chart, you can use the standard line chart widget.
In there you can opt for dynamic series and your preferred datasource. you can also use an advanced setting to change the layout