In one sentence, describe what the following article is about:

The Textra icon looks like two white, horizontal lines in a blue speech bubble on your Apps list. Textra will open up to your inbox. If Textra opens up to a conversation, tap the back button to go back to your inbox. This will open the conversation in full-screen. You can search a chat by tapping the magnifying glass icon in the upper-right corner of your inbox. This button is located in the upper-right corner of the conversation. It will open the conversation settings, and reveal toolbar icons at the top. This button is located next to the pin and trash icons at the top of your screen. Tapping will mute the group chat, and take you back to the text conversation. You will see a green notification box confirming the chat is "Muted" at the bottom of your screen. You can unmute the chat any time by tapping the bell icon again.

Summary:
Open the Textra app on your Android. Tap the group message you want to mute. Tap the  icon. Tap the bell icon.