There are several ways to install Appium on Ubuntu below is using appium image file
Step 1: Navigate to This Link
Step 2: Download appium Image
Step 3: Move image file to desired directory
Step 4: Make file executable using below command
$ chmod a+x appium-desktop-1.9.0-x86_64.AppImage
Step 5: Execute image file using below command
$ ./appium-desktop-1.9.0-x86_64.AppImage
Step 6: Select yes