Ubuntu Bionic Making Menu Launcher - 2
Check if the alacarte Package is there
which alacarte
If Not then Install It with:
sudo apt install alacarte
If Got “User is Not in Sudoers file” then see: How to Enable sudo
Then Launch Main Menu Tool.
Select or Create Menu.
Click on New Item.
Next Click to the Left On the Launcher Icon
Then Browse for the App .png Icon file.
Here Below See How Locating Files/Icons on Linux Command Line
How to Locate Files on Command Line