minecraftWorlds contains each world that has been generated within the current build of Minecraft. Each folder also contains resource and behavior pack folders for any packs that may be in use within the world.
A. Unlike the regular Minecraft which saves the worlds to location %USERPROFILE%\AppData\Roaming\.minecraft\saves\, the Windows 10 edition saves the worlds to %USERPROFILE%\AppData\Local\Packages\Microsoft.MinecraftUWP_8wekyb3d8bbwe\
LocalState\games\com.mojang\minecraftWorlds. The worlds save in different formats so you cannot just copy worlds from the java based version to the Windows 10 version.
Once you've found your Minecraft saves folder, you can copy and paste the location into your file archiver program and extract the Minecraft map from there. The location of your saves folder will be something like this: "C:\Users\yourusername\AppData\Roaming\.minecraft\saves" on Windows.
Most PE maps these days use the .mcworld format. This is a special file just for minecraft. Just click it and it will automatically install the bedrock map into your game no matter what system you're on.