Tutorials must be created by you and your own idea.
If you got idea from elsewhere and revised your own version of tutorial, please include reference and credit original authors.
For example if you found a Photoshop tutorial and wanted to write a GIMP version, you must credit the original Photoshop tutorial.
OK - if those created layers are blank, there is one probable reason. BRL typically operates against a selection that has some content and will produce an outcome from that operation. However, BRL will operate against a 'selection' that has no filled content and it will produce a 'blank' outcome on a new layer. Typically that is caused by the current active layer being the wrong one.
So we need to check that the your selection has been 'filled' with a colour and that the selection filled layer is the current active layer against which BRL will operate to produce a glassy outcome.
It appears to me that the brumby outline has been properly selected in step 2, and I double-checked and triple-checked to make sure I had the correct parameters for the Bucket Fill. However, it doesn't appear that the Bucket Fill actually did anything.