Hi,
My knowledge as far as cron is as follows:
In the user account you would like to run a command or script type in
crontab -e
This will take you into the cron file editor.
The cronjob is setup as follows
30 12 * * * echo "This job will execute now" /*Or whatever your command would be*/
30 - Minute
12 - Hour of the day
* - month day (could be set from 1-30)
* - month (could be set from 1-12)
* - day of week (0-6, where 0=Sunday)
Try the echo command in the user account you are in to echo a message to a file in the directory somewhere.
It should execute the specific time you gave it. Once you figure this out it should be pretty easy to run cronjobs from there.
Here is an example
23 17 22 8 4 echo "Is this working!" > tmp/example.txt
Make sure there is a tmp directory in your working directory.
All you need to do is change the time in crontab with the time you want the command to execute.
Hope this is of help!
Cheers