Chart understanding problem

[SeriousM]

Hi,

I'm trying to extend your chart by a line showing the visitors/converstions over time in order to have a better feeling for the shown values.

The data is already selected but I have very serious problems to get the data into the chart.
I'm new to d3 and maybe I oversee the point where you put the elements into the chart.

Could you please elaborate a little bit how the chart works?

Thanks!!