I have two different 1and1 account, one Unlimited Pro shared server and one VPS -- neither one show a control panel such as you describe so I can't help with using cron that way -- On my sites, I use SSH to the server, create a text file (with nano) that has entries like
*/5 * * * * cd $HOME/httpdocs && /usr/bin/php -q nws-alerts.php > status.txt 2>&1
That code causes cron to change to the directory with nws-alerts in it, then the second shell command runs the nws-alerts.php script and places the listing output in status.txt
save the text file (I called it cronjob.txt), then
crontab cronjob.txt
to enable it then
crontab -l
to list the contents of the cron jobs list.
Several 'gotchas' with cron/linux shell scripting:
1) the files (like cronjob.txt) have to have unix line endings only (LF) and NOT Windows line endings (CR, LF)
2) cron only knows your home directory and you need to change to your document root to have your script run correctly
Hope this helps...