There should be an entire folder full of files for one map. if you downloaded it form someone it should be in a folder in rar/zip file. the folder is what you want to put into the /maps folder. after that just reload shogun 2 and it will be there under the name the map_info.xml file indicates.
Actually it's the name of the folder that shows up in the map list. For custom battles at least.
Mod workshops are for a reason. Thread moved from TWS2 GD section to S2 mod workshop\mapping section.
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