They aren't that hard to do. Just where it says "Path to file" or "Command" just put the URL of your script. Don't have the script output anything unless you check your log files. Easy as that. The times and such are configurable in the "regular" view, rather than advanced. But every 15 minutes.... geee....
Read this
Shows you how to set up a Cron Job in cPanel...

And you can even set it to run every 15 minutes of every day of every week of every month. The command once again would be the url to the script you want run. Save it and you're done.
ah yes, and please read the rules. no job postings (and what you posted is essentially a job posting: do service for compensation).