Combine CSVs from Folder - Separate Function

As a matter of fact (or a matter of opinion?) these objects cooperate just fine:

one of your files is the Sample Binary in binary form,

the parameter Sample Binary Parameter1 is pointing to the Sample Binary,

the "Transform Sample Binary from Data" is an example query that transforms your Sample Binary to a table,

the function Transform Binary From Data is actually the example query wrapped in a function.

Any modifications in the example query will be automatically promoted to the function.

The function has one parameter with exactly the same name as the parameter that is pointing to the Sample Binary.

So in the example query that parameter is pointing to the Sample Binary, but in the function it points to the parameter that is supplied to the function being the contents of the files in your folder (as you can see in the step "Invoke Custom Function1" step in your query). So the parameter is just a trick so the exact contents of the example query can be wrapped in  the function without any modification.

In the "Removed Other Columns" step, other columns - but the filename and your tables - are removed from you navigation table (or in other words: your file list). If you want other columns from your navigation table (e.g. "Date Created") you can modify this step using the small wheel and (un)check the columns you (don't) want.
Note: for this step to work fine, don't remove columns from your navigation table before you choose "Combine Binaries".

In the "Expand Table Column1" step, your tables are expanded,

So the place to make modifications to individual files is the example query, except for any data type changes as these will get lost in the last step that is added to the query in which the tables are expanded.

I raised 2 ideas regarding this subject:

Make "combine binaries" independent from existence of a particular file

Preserve data types when expanding table columns

and I created a 21 minute video in which Excel files are combined using this functionality (you can jump to various parts of the video via links that are supplied below the video).