Here is the old tutorial which is still relevant but complete: http://gavagai.se/blog/2016/01/25/getting-started-with-gavagai-explorer-2/
Or a youtube playlist of short videos explaining the functions of The Explorer.
https://www.youtube.com/playlist?list=PLIB1-JPnS3k_OwvPl_gTgbUPSkaYUYBiu