Hi,
First try to create Bly Ray Image Under option ‘Output” Select BluRay Image, and also select the destination to create Image and click on Build, It will create a BluRay Image with extension of .iso. Now to burn BluRay Disc, you need to Select BluRay Disc under ‘Output’ Option and Below under ‘Source’ Option select BluRay Image instead of current project and Select the destination where you have put .iso Image, Then click on Build and it will burn BluRay disc.
In simple , First create an Image then Burn that image to BluRay .
I hope, it will help you.
Thanks