The Guide shows you Step-by-Step How to Create a New Application Launcher inside to the Main Menu on SparkyLinux Eris Mate Desktop.
The Practical Example Here Illustrated is About Adding the Firefox Nightly Entry inside to the Internet Section a SparkyLinux Mate Desktop.
The Technique is Useful for Adding Any New Custom Software on a SparkyLinux Mate Desktop.
To the Post Bottom there is a Link to Guide for Installing the Firefox-Nightly Browser for SparkyLinux.

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Right-Click on Desktop > Create Launcher
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On the Create Launcher Select the Icon
Here Below Link to Article with Tutorial 4 Locating Files/Icons Under Linux.
Linux How to Locate Command