Obtaining file path in QGIS Training Manual

6.2.5 Try Yourself: Convert Layers’ CRS

…

8. Repeat this process for each layer, creating a new layer in
the vector_analysis.gpkg GeoPackage file with _34S appended to the
original name and removing each of the old layers from the project.

link: https://docs.qgis.org/3.16/en/docs/training_manual/vector_analysis/basic_analysis.html

I appear to have successfully added roads_34S to the vector_analysis.gpkg file:

My goal now is to repeat the process with restaurants, schools and buildings. I open the Save Vector Layer as … dialog and enter the Layer name and find the correct CRS. Now I want to use the ellipse button by file name to find the file path:

I search for vector_analysis.gpkg to obtain the file path. When adding the roads layer, I put the new package into a folder, myExerciseData, reserved for files that I create. I click the button and get the following, showing that the filenames are inactive.

Since the file names are inactive, I cannot open a file, which seems to mean that I cannot save the restaurants_34S layer with the new CRS to the file vector_analysis.gpkg. What have I missed? Do I have to enter the file path manually?

I try entering vector_analysis.gpkg. I click on Save. I get this dialog:

What has gone wrong here?

The following was added after Ben W’s response.

I filled the boxes in the order in which they appear, as in the following image. The filenames remained inactive as above in the Save Layer as... dialog.

When I selected OK, I got a new dialog box:

Does this offer a clue? Are there any OS X users on this forum?