The easiest way is to use the Logitech Harmony Hub integration. No custom code required. The harmony hub with the button remote list for about $ 150, but is often on sale at Amazon or Best Buy for about $99. it’s not a perfect integration because you have to work with the concept of harmony activities, but it does work for many things.
https://support.smartthings.com/hc/en-us/articles/205653834-Logitech-Harmony-Home-Hub
Another alternative is to get the same global cache unit featured in the article you linked to (by the way that article will only work for Vera, not SmartThings). Global cachet is a popular Wi-Fi to IR bridge. There are some community members using it was SmartThings, but that as you noted it’s not simple. That approach will require using a PC or Mac as an intermediary and some custom code. So it gives you more granular control then with the Harmony, but it’s harder to set up. Or you can use RoomieRemote ( a smartphone app with an annual fee, recently changed their name to Simple Control) to control the global cachet. Still somewhat more complicated than using Harmony.
A third alternative is to get a Z wave device that can broadcast IR and there are a couple of community members using one, the remotec HVAC ZXT120. It won’t require a laptop as a bridge, but it offers many fewer commands then either harmony or global cachet. So it just depends on the particular device you want to control. It’s most commonly used for a window air conditioner as it represents itself as a Zwave thermostat.
So there are at least three options that people are using. It just depends on the specific devices you want to control, and exactly what you want to do with them.
The Harmony works great for things like turn on the TV to ESPN while also turning down the lights. Or turning off the home theater devices while locking the door and turning off the lights as part of a good night routine. Where it gets tricky is the granular commands like adjusting the volume up and down. That’s where the Global Cache has the advantage.