First off, only polling automations can be scheduled for execution. Webhook, or "instant" automations like the following cannot be scheduled:
Instant automations are executed whenever the trigger app(s) push data to our system.
There are two types of polling automations. The first is one that executes periodically, e.g. every 15 minutes. You can adjust the polling schedule by selecting the "Schedule" menu option:
Then click the polling schedule link to change the interval:
Polling automations can have execution windows defined to run the automation only during certain time windows on certain days, e.g.8am-5pm M-F. Click the "edit" link next to Execution Windows:
To not have an automation run on a certain day, set its start and end times to the same value as shown on Saturday and Sunday above.
A second type of polling automation is one that uses a Date/Time trigger to schedule its execution. A Date Time trigger can be added to a polling automation like so:
Note: when saving new automations, choosing the "scheduled" option automatically adds the Date Time trigger.
Then you can choose the desired trigger schedule and configure it:
Scheduled automations do not have the ability to change the polling schedule, but can still use execution windows: