No logs visible, although it seems Promtail is configured fine

I just created new free account and followed configuration documents:

-it seems Grafana Data Source settings are OK, they are configured automatically, test says “Data source successfully connected.”
-I installed promtail as per documentation. Created config file, added token to it, started it from Docker and it seems it runs OK

Now I created new dashboard from that datasource, picked Logs for visualisation but nothing is there. How I can debug this, how I can verify that data is actually sent? Or to find problem wherever it lays.

Thanks !