As you have not provided example file, I assume that the "file" I copy pasted is what you have

You should be able to ignore headers by just utilizing settings, for footers, I think you will have to remove them afterwards
Names Default To Here(1);
dt = Multiple File Import(
<<Set Folder("$DOWNLOADS\843237\"),
<<Set Add File Name Column(1),
<<Set Import Mode("CSVData"),
<<Set Charset("Best Guess"),
<<Set Stack Mode("Stack Similar"),
<<Set CSV Has Headers(1),
<<Set CSV Allow Numeric(1),
<<Set CSV First Header Line(3),
<<Set CSV Number Of Header Lines(1),
<<Set CSV First Data Line(4),
<<Set CSV EOF Comma(0),
<<Set CSV EOF Tab(0),
<<Set CSV EOF Space(0),
<<Set CSV EOF Spaces(1),
<<Set CSV EOF Other(""),
<<Set CSV EOL CRLF(1),
<<Set CSV EOL CR(1),
<<Set CSV EOL LF(1),
<<Set CSV EOL Semicolon(0),
<<Set CSV EOL Other(""),
<<Set CSV Quote("\!""),
<<Set CSV Escape(""),
) << Import Data;
dt = dt[1];
rows_to_delete = dt << Get Rows Where(Starts With(:Parameter, "! "));
dt << Delete Rows(rows_to_delete);

-Jarmo