Regimental drummer: where is the top of the deck? (Thronebreaker: The Witcher Tales)

Please tell me, something blunt and I can't understand what map does? Put drummer and look at the deck: first card blitz, if you count from left to right, Spearman, but using the order from the drummer goes crossbowman or something else? Maybe the top of the deck at the bottom?) Or right to left must be considered?
After using drummer all some kind of nonsense going on. Seven cards remained in the deck, three of them cocinera. Used the order of the drummer, got some map and I see that the deck has six cards, open deck, and there are only 4 cards (instead of three K left one). Cosigner dying in the deck)
PS. Again after using drummer in the deck was left alone cosigner of the three. And the card went from the middle of the pack. That is, the top of the deck in the middle? I don't understand.