It’s the blue icon with a white paper airplane inside. You'll usually find it in the app drawer. The conversation will appear. It’s at the top of the screen. A list of members in the group will appear.  It’s the square chat bubble near the top-right corner of the window. This opens a conversation. It’s at the top-right corner of the conversation. This sends your phone number to the selected contact so they can add you to their address book. At that point, you’ll be added to each other's contact lists.

TL;DR in Indonesian:
Buka Telegram pada perangkat Android. Sentuh grup dengan kontak yang ingin dicari. Sentuh nama grup. Sentuh anggota grup yang ingin ditambahkan sebagai kontak. Sentuh ikon pesan. Sentuh ⁝. Sentuh Share my contact.