FFT megaCore usage problem

Thanks for the guidance on testbench

I have read the example code you provided, so when I make simulation at modelSim, do I need to include all files in the project to run or just put fft_h.vhd and the test_bench_example.vhd?

Do I need to use the command like

FILE file_in : TEXT is in "data_real.txt";

FILE file_in : TEXT is out "dataout.txt";

VARIABLE line_in : LINE:

VARIABLE line_out : LINE'

VARIABLE input_tmp : INTEGER;

VARIABLE output_tmp : INTEGER;

and command like READLINE()

for declaring the input and output files to provide inputs and obtain output of FFT when using the testbench file you provided?

I notice there is a file fft_h_tb.vhd generated by the FFT megaCore, what is the difference between these 2 files fft_h_tb.vhd and fft_h.vhd?

I also attached the all vhd files of my project. let me know what I should do to improve my vhd coding and integrate the simulation command to them? Thank you.