--- a/Campaigns.wiki	Wed Oct 30 02:59:24 2019 +0000
+++ b/Campaigns.wiki	Wed Oct 30 03:00:39 2019 +0000
@@ -78,7 +78,20 @@
 A_Classic_Fairytale-first_blood.desc="Help Leaks a Lot to complete his training and become a proper hedgehog warrior. You will be trained in the art of rope, parachute, shoryuken and desert eagle."
 }}}
 
-== Campaign progress ==
-Initially, only mission 1 is unlocked. To unlock more missions and to mark missions and the campaign as completed, you must set campaign variables. 
+== Campaign variables / campaign progress ==
+Campaigns support campaign variables which allow to store arbitrary values about the campaign in the team file. Most importantly, the campaign progress is stored here. This uses the functions `SaveCampaignVar` and `GetCampaignVar`. Note that `SaveMissionVar` and `GetMissionVar` do *not* work in campaign missions.
+
+Initially, only mission 1 is unlocked. To unlock more missions and to mark missions and the campaign as completed, you must set campaign variables. For linear campaigns, you can use this idiom:
 
-Read [ConfigurationFiles] to learn how campaign variables work.
+{{{
+-- To be called when mission 5 was won:
+local missionNumber = 5
+local progress = tonumber(GetCampaignVar("Progress"))
+if progress == nil or progress < 5 then
+    SaveCampaignVar("Progress", "5")
+end
+}}}
+
+For non-linear campaigns, a more sophisticated unlocking is available.
+
+Read [ConfigurationFiles] to learn how campaign variables work in detail.
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