What are the musts and must nots for config file and data file?

[moferry96]

Hi. I think the documentation is not enough for getting Matarank up and running and the process is like a trial-and-error cycle. For example, you must have ranking events cause the validator says:

event types check = FAIL (0 ranking events found)

but it is not mentioned in the documentation. What if a system does not track ranking events? Is it Ok to add only 1 ranking event to avoid the error?

Or another one is for features in the config file. For the source field of a feature, what is the convention of it? In the docs, there is an example like "source: item.popularity" but it does not work, and in the demo config file it is: "source: metadata.popularity". Which one is correct and what is the difference? because in the demo config file, we also have "source: item.something".

I would appreciate your guidance.