How to manage timers/cronjob on ubuntu core?

Hi, a friend told me that ubuntu core is not mroe using cronjob and instead it uses .timers. wher can I find snaps and documentation about these timers?

you would package your service/daemon as a snap and set a timer in the snapcraft.yaml apps: block of it … see the timer entry in:

the format you can put into this field is described at:

I have fixed the problem with: