Weather34 template - How to make the graphs appear right?

Hello,

I am trying to use the template I found here (https://weather34.com/homeweatherstation/#_). It looks nice. However, I cannot find how to make the graphs (e.g. annual, monthly and daily temperature) appear correctly.

Where such data is stored (which txts) and where should I place the txts path in order to get the graphs?

Furthermore, is there any way to make archive from previous years appear somehow?

Thank you in advance,

Stavros