Enable macro - LibreOffice


I want to enable macros on LibreOffice so i can use a file that has macros.

On my Tools->Options->LibreOffice->Security->Macro Security->Trusted Sources i have a blank scree.
How can i add a trusted source for macro on LibreOffice 5?

Thank you?

I changed Security Level from High to Medium and it worked.
Tools->Options->LibreOffice->Security->Macro Security->Security Level