Add a test suite to a test suite collection. In your test suite collection you can configure the timing of the execution in Test Suite Scheduling View.
Click Schedule, the pop-up will appear to remind you to not turn off Katalon Studio until the test suite collection is executed.
The Next run field will contain the date of the upcoming execution of this test suite collection.
If you want to reschedule, you just need to input a new time and hit Schedule again. A pop-up will inform you that the old schedule will be overrided.
Now the test suite collection will be executed at the updated time.