If you want to use Active Directory Lightweight Directory Services (ADLDS) on Windows 10 you will have to enable (install) it from the “Windows Features” dialog:
Control Panel \ Programs and Features \ Turn Windows features on or off:
After the installation you can start the configuration of ADLDS by starting the "Active Directory Lightweight Directory Services Setup Wizard":
Found at: C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Administrative Tools\Active Directory Lightweight Directory Services Setup Wizard
To add users to the ADLDS you must start the ADSI Edit:
C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Administrative Tools\ADSI Edit
Now the user is created, you can set a password by using the “reset password” option.
Just right click on the user: