This document describes how to create an Azure Container Registry task using an ARM template.
One thing that isn't clear from the document and the reference is how to create an ACR timer task with an ARM template. Effectively doing this same as the az acr task timer add command.
Is it possible to add a timer to an ACR task with an ARM template?
Of course, Yes. You can find the timer trigger in the template of the ACR task, and here is an example for the timer trigger: