Hello!
There is no other way to launch a user-created campaign for Heroes 2 than simply play each scenario one after another as singleplayer scenarios. The campaigns are simply a selection of singleplayer scenarios which should be copied to the Maps folder of the game.
Some campaigns may have plot arranged in that way so the sequence of scenarios can be freely varied by a player.
Some campaigns may have additional text files included in the archive so that you can understand the plot more.
Besides, you can check some
here.
Specific custom campaign menu appeared only starting from Heroes 3.
Cheers!
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