That is expected. If you cron job is setup properly, it should update your site automatically. 

And what schedule should stand in the cron?

I do not know how your cron job is setup. You can go to Studio > Dashboard > click the down arrow by Host Tools and choose "Server Audit".. Scroll down and you should see how your cron job is setup there. Like this:

SHELL="/usr/bin/bash" *    *    *    *    *    /opt/plesk/php/7.1/bin/php -q /var/www/vhosts/mywebsite.com/httpdocs/periodic/cron.php

Those 5 stars you see there..  * * * * * mean I have mine setup to run every minute.