Copy and rename list of files all with the same name

Hi folks, first of all please help me then i'm going to describe my
difficulty,

I guess it's a very simple case but unfortunately not for me becasue
I'm a beginner not only in idl but also in general programming.

PROBLEM:
I have a list of files all with the same name and I would like to make
a copy in a common folder. To avoid overwriting I have to rename each
file, e.g. with a progressive number. Basically, I have three steps:
(i) make a list of files, (ii) rename each file (file_move) (iii) and
then copy file_copy.
I'm assuming that I should repeat the process inside a loop for each
file

DIFFICULTY:
In the last copying step I'm not able to define the correct syntax for
the file_copy function.

Do you think that my approach is completed wrong? Is it a more
complicated case and should use another solution?

I'm re****ting the codes that I wrote:

;GET LIST OF FILES
Path = 'C:\source\'
list = file_search(Path,'spectra.txt)

;FILE LIST ORDED
str_num = stregex(list, '[0-7]+.std', /extract)
idx = sort(str_num)
list_orded = list[idx]

;READ IN ORDER THE FILE LIST
for i=0, n_elements(list_orded)-1 do begin

       ;DEFINE DIRECTORY OUTPUT
        fdir='C:\destination\spectra'

       ;DEFINE A SUFFIX FOR THE OUTFILE NAME
       suffix=strcompress(string(i),/remove_all)
       a=strlen(suffix)
       for k=0,2-a do suffix='0'+suffix
       out_fname=fdir+suffix +'.std'

       ;(III) COPY FILES ????? I think I should inset the loop's index
"i" and copy to out_fname
        file_copy, i, out_fname
endfor
end

Thanks in advance, Cico