hello and welcome to the forum,
the forum has many examples of using cron jobs.
https://forum.rclone.org/search?q=cron
https://forum.rclone.org/t/what-am-i-missing-in-crontab-executing-the-cron-files/10926
the key code is
if pidof -o %PPID -x "$0"; then
** exit 1**
fi
or use flock
Script works but i have some stalling/ major issue
flock -x -w 5 200 || { echo "script is already running"; exit 1; }