How do you send a message on a certain day of the week?

Every Monday I need the trash to be taken to the curb. When I used Hospitable there was an option to send a message every Monday night reminding the guests to put the trash near the curb. I'm not seeing how to do that in ownerrez. 

This is a commonly requested feature and I believe not possible at this time--however, there is an active feature request in the Feature Requests forums, so if this is important to you, you might want to upvote that feature request:

https://www.ownerrez.com/forums/requests/trigger-for-exact-day-of-week-trash-reminders