crontab has been causing me a wee bit of confusion too but
I take it you want to run the command every minute?
I was trying something similar and wondering why it wouldn't work till I worked out
* 00-23 * * * /home/oracle/runme
will run the command every-minute for every hour of the day, maybe there's a better way but I don't know.
to create the crontab entry for a particular user while logged in as root
crontab -e username
then add the entries
or as logged in as the actual user
It's more a lack of understanding of crontab that caused me problems but, problems are there to be overcome