Rule explanation SOS Munchkin Zombies

[IliasM]

Guys, yesterday i played for my first time and i think i learned every rule, but at the end of the game me and my friends(they are pros) faced a problem. The one was lvl 9 facing a monster. one guy throws wandering monster with a monster and its not enough. the other guy throws another wandering monster with a monster and its not enough. So then i throw this card that can be used in one battle and others can throw in battle monsters. I dont know how this card is called in English but in my country is called something like calling for attack, mars attack or sthg. Card says all players starting from left can throw a monster. The question is do i also throw a monster too (I use the card). Do I throw a monster first?Can each player use only one monster ? Thanks in advance, plz help