It's not quick and not that easy...
 

... but this game is very engrossing. You can save battles in progress so you can pick them up in breaks. Just completed Mission 1 on my fourth attempt. Good job I've never had to direct the defence of an installation. :8

Edit: you have to complete the Roman, Mediaeval and Napoleonic missions before you get to play at being Dowding. Interestingly, his advice is pertinent to the Mediaeval battle.

adr