Licenses can be added for DBXL using the DBXL Admin Tool (DAT) or using the DBXL Licensing web service.
To add a license via web service, you must open a web browser on the server where DBXL is installed. Copy your license file to that server, and make a note of the file path.
In your web browser, navigate to:
http://<servername>/QdabraWebService/default.htm
with <servername> replaced with the correct address for your install.
Select DBXL License Management from the Web Service descriptions:

Select AddLicenseFromFile from the DBXL Licensing page:

The method page opens:

Enter the contact email for your license. Enter the file path to the local copy of the license:

Click the Invoke button:

The XML response will show Success as true or false. If there are any errors configuring the license, those will be returned as well. For example, if you add a license that is alread installed:

Be sure to check out the other methods for licensing as well. You can use GetLicenseInfo2, for example, to return the information about installed licenses, and then use the serial number returned for the RemoveLicense method.