If you just want to add capacitive touch sensing to your project, a quick search of your favorite low-cost components supplier will reveal breakout boards to take care of this easily. On the other hand, according to YouTuber GreatScott!, that’s cheating. Perhaps he would clarify to say that it’s cheating if you don’t understand the underlying concept.
If you’d like to know more about how this sensing method works, GreatScott!’s video will give you a great introduction to the concept, as he creates a capacitive sensor with an Arduino, capacitor, and a couple of resistors. When he touches the capacitor lead, he acts as a capacitor himself, more than doubling the time it takes to charge/discharge the capacitor. The Arduino used stores this value and compare this time to a threshold value, which acts as a simple input.
The prototype works well, but when GreatScott! attempts to use this circuit to control his desk lamp, things got a little wonky. Regardless, the video provides a great introduction to this tech that you can either build upon, or sub a breakout board in while understanding the underlying concept. He’s quick to note that his actual lamp circuit isn’t a safe electrical design, so make sure you wire things correctly, especially when working with mains power!