If a monster effect causes you to gain any Conditions for the next Level, find the relevant Condition Card(s) in the Condition deck and place it next to the Monster Sheet. When you reach the end of a Level, discard all previously active Conditions. To mark that the new Conditions are active, move them from beside the Monster Sheet to beside your Character Sheet. These will affect your character for the duration of the next Level. Certain Encounter Cards allow you to get rid of active Conditions.
If a monster’s combat roll would cause you to gain a Condition you have already gained for the next Level, re-roll it. If one of your Skills allows you to ignore a specific type of monster effect, nothing happens when that combat action is rolled. You got lucky!