Smartthings doesn’t have its own rules engine as such, the built-in smart lights smart app is the closest. But it’s a that, if, structure. First you select the device, then you say what you want to have happen with it.
There are two very good third-party rules engine apps, but unfortunately the current OAuth bug which is affecting the UK means these do not work for UK accounts at present. I’ll put the link to the information about them here for future use, and I know all the developers (who are all active community members here) are trying to do what they can from their side but really it depends on a SmartThings architecture change that is impacting most third-party integration is at the present time. Including, unfortunately, the official IFTTT integration.
There are about 12 different ways to schedule events in SmartThings, so here’s the overview of that as well. But it may not be what you were looking for.
Progress on the Oauth issue is being followed in the following topic:
Do you to the Oauth problem affecting many third-party integrations, simple rule builder will not work for UK account at this time. Nothing you can do about it it’s an authorisation issue on the SmartThings side.
SmartThings has said they know about it and are working on it but it’s quite a large problem to fix. When it is fixed, many different third-party integration should become available again.
The issue is being tracked in the following thread: