After installation you will find all cronjobs unter Administration->Cronjobs
In this area you can edit or execute cronjobs. Edit means you can edit execution periods in crontab but you can't edit content of cronjob(see screenshot below).
The creation of new cronjobs in backend of CONTENIDO is not possible because of security reason.
That means you have to upload new cronjobs to your server via FTP or SHH access.