Not an answer to your question, but I have myself started playing with Google Data Studio to make visualizations from both sheets and google fit data, inspired by this blog post:
I’m not an “expert”, but I have some experience. I clicked the link you provided, and saw numerous #N/A! errors on most of the sheets. I also saw many #DIV/0! errors on the Dashboard sheet. If you specify a particular sheet and cell where you would like to start, I could probably point you in a useful direction. Ultimately, I expect you will find that getting the right data in the right cells (either by copy/paste or by uploading a file) will solve most of the problems all at once.