Maps are being downloaded on: https://maps.adventurecraft.gq/
The maps uploaded here have been uploaded by the official creators and have been checked for accuracy.
In order to download a map, you first need the official launcher, which can be downloaded after a successful login with your Mojang account.
By clicking the map code, the launcher will open up and paste the code.
The button to the right starts the download, an indicator appears with the progress of the download, the subsequent unpacking can take a long time depending on the PC.