The above answers are correct. Official answer from Academy Games:
Yes, using your example given, in round 1 of Firefight 01: Partisans, the German units enter just like reinforcements, paying for movement in the same way as described in the rule book. You can also delay their entry for a subsequent round, just as you could with reinforcements. Unless otherwise specified in the firefight setup, this is how all setups like this work in CoH.
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When Reinforcements enter, they move onto the map, paying for it with AP, Opportunity action, CAP or a card. Individually or as a group movement (possibly transported). (Rule 5.5 Unit Reinforcements)
But when a Firefight says that units enter as part of Setup, do they all enter at once, un-activated, without cost - or do they enter just like Reinforcements, paying for it? If they enter like Reinforcements, may they also delay entering for later, like Reinforcements? (Example: Firefight 1 - Partisans.)