You can follow almost every parameter from Google Ads platform, but you need to follow one rule to make it work:
Values in the query need to follow Google API documentation. You can find most of the supported columns here.
Now, let's get to adjusting the template.
Browse this list of metrics and find the column you would like to export. Let's say you are interested in tracking Average Cost per Click. The API call to download the metric is parameter AverageCpc.
Go to your connector and enable the Advanced Editor. Then find the fields section in the query.
Add the AverageCpc.
The last step is to add the parameter Time on Page to the dataset as a metric. It is very important as to call a parameter without a definition assigned to it, can lead to an error. To do this, add the new metric to the "transform list".
The Code defines the name of the column
The Source parameter is referring to the source parameter above the transform parameter. JSON will go and check if there is the same source (in this instance "AverageCpc") and if it is, it will populate the column with that data.
After that, you are ready to save the adjustment and test it in the preview. The results in your Excel sheet from your newly customised template should look like this: