Icon change

I want to change the generic app image icon for Manager to an icon of the application. Using Ubuntu Linux OS desktop. Does anyone have the instructions for this? And in future can the Linux download be created with the right icon in it? Had no issue with a Windows 10 setup.

Unfortunately AppImage has no native support for it. But you can create separate desktop file.

See https://linuxconfig.org/how-to-create-custom-desktop-files-for-launchers-on-linux