Want the scoop on Paladins’ siege mode coming in Closed Beta 22? Hi-Rez has posted an updated FAQ to answer players’ questions. The objective of the mode is pretty simple: The first team to get four objective points wins. Getting these objective points involves rounds of capturing points and escorting payloads before the timer runs out.
The FAQ also addresses Burn Cards, special one-round buffs players can purchase for each round using credits obtained throughout the match by capturing points and killing opponents.
Source: Siege FAQ