Hi, when you press the touchlink button the app shows a touchlink message for a few seconds, just like you described. That means the touchlink was executed. The light should blink, if not, try the touchlink again. After the light blinked, tap the search for lights button and your light should be found.
There was a bug in Hue Essentials that the search for lights button did not work. Please update to the latest version on the App Store (version 1.7.3 has a fix).
Please let me know if you have any further questions.