Step-by-step – Telegram Flatpak Ubuntu 18.04 Installation

Installing

2. 2. Setting Up Flatpak

   How to Setup Flatpak on Ubuntu 18.04

   Flatpak Ubuntu 18.04 Installation Guide

   Flatpak Ubuntu 18.04 Setup

3. 3. Installing

   Then to Install Telegram App on Ubuntu 18.04
   To Setup the Repo play:

   flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo

   For further Insight see the Flatpak Official Documentation.
   And after:

   flatpak install https://flathub.org/repo/appstream/org.telegram.desktop.flatpakref

   The Flatpak App Setup do Not need the sudo Command because then it Runs confined into a Sandbox.
   Authenticate to Update the Repos:
   
   Then Confirm with ‘y’ for Installation.
   And Wait patiently until the App is Downloaded, Built and Installed…
   The first Flatpak App Setup may be quite Large & Long because it need to Setup some Base Components.