I have an Applescript that simply opens a Dialog Box, asks for a user input and runs a Terminal Command and spits out the answer. It works great in AppleScript Editor yet I am trying to work out how I could package this Script File along with an icon to make a Mac App for my personal use. Thoughts.
In Script Editor, select File > Save As and set File Format to Application. (In Mojave and later, the Save As choice in the File menu is not visible unless you hold down the Option key.)
Open Bundle Contents drawer and see the applet.icns file, copy your icon to that.
See "Saving a script as an application" in Script Editor help.