Shell Programming and Scripting

Hello guys it´s a pleasure to type with the unix community...I´m new in shell script and I need to insert into a #!/ksh a statment that will check if a file that I´ll receive from another script is arriving in the first working day of each month:

let´s say that I´ll reveive the following files per month:
ftp_ksh.txt
user_code.txt
indx.txt
I need to know each of those files arrived in the firt working day of the current month september was monday the 3rd. October will be monday the 1th.
Can you help me?

You can use -f option to check for whether file is exist, then put the scrip under crontjob to run on monday of each months

eg.

if [ -f ftp_ksh.txt ]; then
#send email to yourself
fi