When you create component, add a property called 'componentGroup' with a value 'customApp'
Now, in the page where you want to enable the same, click on 'design mode' of the side kick (3rd Icon at the bottom) and select the customApp checkbox and click ok.
Once you are back on the edit mode of the page, you should be able to see 'customApp' in the side kick.
// here under the Create an AEM 6 Touch UI component section, we can see that there is a Group option in create component dialog box.
Group: The group in the side kick where the component appears. Enter General (any name). (The herotext2 component is located under the General heading in the Tocuh UI side rail. Also appears in General in the classic view sidekick.)