This wikiHow teaches you how to log in to Telegram when using an Android device.
Steps

Step #1. Open Telegram on your Android
This is the blue circle with a white paper airplane in it. You can usually find the app on the home screen or in your app overview.
- If you don't have the Telegram app for Android, open the Play Store, Search Telegram and then tap TO INSTALL.

Step #2. Tap on Start Messages
It's the blue button at the bottom of the screen.
- If it's your first time using the app on this phone or tablet, tap OK when prompted, then tap TO ALLOW to allow the app to receive calls and text messages.

Step #3. Enter your phone number and tap the check mark
Telegram will send you a text message to confirm the number.

Step 4. Enter the SMS code and tap the check mark
The code is the number in Telegram's text message. You are now signed in to Telegram.
- If it's your first time setting up Telegram, tap TO ALLOW when prompted to allow the app to access your contacts and media.