When the attributes are created they must be assigned to a class, for BoardGent this class is Computer. To do this, perform the following steps:
Open the Schema Console
Go to Classes folder
Locate the computer class
Go to the properties and in the Attributes tab
Go to add button and find the Attributes of Boardgent
After being assigned, we carry out the validation with any object of the Active Directory. Note: we must close the MMC console where the Active Directory Schema is so that the changes are processed