Add cronjobs in your vps server
Login to your server first with ssh:
List the existing cronjobs:
Add new cronjobs: (first it will ask you to select a text editor)
After saving the file, the cronjobs should start working.
Every command has these 6 parts:
(minute, 0-59) (hour, 0-23) (day of month, 1-31) (month, 1-12) (day of week, 0-6 / SUN-SAT) (command)
For example to if you want to clean up a folder every day at 3am:
0 3 * * * rm -R /var/www/temp/*
or do it every Sunday and Thursday:
0 3 * * 0,4 rm -R /var/www/temp/*
Check out these links, they can help you understand how to place the values and run the cronjobs in the schedule you want.