Now that you've prepared the schema and have the Developer tab available in Excel, you can export an XML from Excel.
Open your metadata file in Excel
Click on the Developer tab
Click on Source
From the XML Source window that the Source button created, find and click on XML Maps...
Find and locate the schema that you previously prepared and click OK, this will display your schema in the XML Source window
Having a valid schema and a cleaned up metadata file will help the next process go smoothly!
Click on the field name within your metadata file and double click on the corresponding schema location in the XML Source window, this will map the information in that field to that element
As Title is the first field in your metadata file, the first schema element that you will map to will be named title or an element that you wish to hold that information (understand that you can name these elements whatever you wish, it is just easier if you name them accordingly)
After each mapping, click on "Verify Map for Export...", this will do just that--verify that the fields are mapped correctly and will export properly
DO YOU MAPPING IN SEQUENCE. DO NOT SKIP A FIELD. Even if you go to column F and then go back to column C, this will cause an error and will not allow for export.
It is not necessary to map filename, as Identifier will be the filename. This may change. (2017-07-31)
Once all of your fields have been mapped and verified, click Export at the top, this will create an XML