The following info is in the links that Caty gave you, but your English is not good so this might save you some time:
As there is not enough space in the internal memory for the map, change the name of the unlocked gmapprom.img to gmapsupp.img and place it in a root folder named 'Garmin' in the microSD. i.e. x:\Garmin\gmapsupp.img [one map only supported]. Or for multiple maps <any_name>.img in 'Map' folder of sd works too. e.g. x:\Map\CNNT_EU_2016_10.img.
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