In Home Routines you first create a routine, then schedule it afterwards, rather than selecting a calendar day to place it on like an event.
You can create routines for different days of the week, or use a bi-weekly or monthly pattern. Just create a new routine (e.g., “Wednesday Mornings”) then open it. Then touch the routine schedule icon at the bottom of the task list. It looks like a little calendar, and probably says something like “Show every day” at the moment. Once you touch the routine schedule, you can go on to select a routine type – weekly, bi-weekly, monthly or manual – and the days you would like the routine to appear and reset.
If you schedule a routine reminder, it will be active on every day the routine is shown. This page of the help has a guide to the different schedule choices:
On the Home screen, you can use the All/Today button in the top left corner to toggle between the list of routines you have scheduled for today, and a list of all your routines.