hard to explain to you, generally you must understand all single command (and I assume you know).
4 step to create a script
1. create a file
2. edit the file, example as below list all files in /etc:
3. save the script
4. set the script executable
chmod +x script.sh
To run the script, simple type ./script.sh in command prompt. It will show you the results.
Please convert it to suit your need. About the scheduling you need to use cron. This one later, don't make you confuse.