How do you use and STOP Crontab?

I need a Perl script to run every Tuesday at exactly midday. Rather than manually running it every time, I've heard that 'crontab' can be used, and have seen imformation about it here and on other web resources. However, before I attempt to use something I know nothing about, a few questions:

1. I have a virtual server with a hosting company (WebFusion.co.uk) which give me ssh telnet access - will this provide me with a way of getting the line into the crontab file?

2. What exactly do I do to initial the schedule? I see I write a line and save it as something like cron.txt, but then what? Do I Telnet in?

3. How do I stop the schedule, for example if I get it wrong? Do I simply delete the line from cron.txt and then add it to the crontab again?

Thanks for your help in advance!

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1) Ask them
2) It will be initialize automatically if the syntax is correct and of course, you need to have permission from your host. The best bet is to "ask them"
3) Just uncomment the line with #.

The syntax and path of your configuration file is OS dependent. Even NetBSD, OpenBSD and FreeBSD all have different syntax and different location.

Just check with your host.