There's 3 documents that give a pretty good start to using the Mission Editor:
GoebelsAICreationGuide.pdf (also called Warbirds AI Creation Guide.doc)
https://drive.google.com/open?id=1LCPDnwpKvlwWZcuktbxmAwxiJrzEugawMission creation guide.doc
https://drive.google.com/open?id=17RAnYYKCkvgqCKo5uLZ8LQsentLWiLlMModelingStrategicAI.pdf
https://drive.google.com/open?id=19dwRzGnScsyhoc5i8hnW07_SV3-RQHXMYou'll also need some extra info:
1. Vehicle IDs from the pnames.txt file in your WB root directory. Be aware not all the IDs will give you flying models as used online. Definitely ignore those with -32 in the 4th column and stick with planes you find online as given by the plane description.
2. Some WB dot commands in wbcommands.doc in your WB help subdirectory. Those 3 documents above tell you which commands are relevant to running AI mission files.
You can only run missions you create when you are in offline mode. In the online arenas the GENERALs (GOERING or whoever) are the only ones with permission to run the AI missions.
The AI planes do fly somewhat differently to the ones controlled by players.
Let me know if those links don't work.