Hey dbhj7! The Android menus differ a little bit from one OS version to another and from device to device, so starting with a new one can definitely be a bit of a learning curve. I took a look in the User guide & Getting started: Samsung Galaxy J7 and found these instructions:
Send a Message to a Group
You can send a text message to members of a group.
1. From a Home screen, tap Apps > Contacts.
2. Tap Groups, and then tap a group.
3. Tap More > Send message.
4. Type your message and tap Send.
Can you try that out and see if those options show up for you?
Marissa, thanks for the access Info for groups. Now I know where to go to
see my groups.
Happy to help! I'm glad that worked - sometimes menu options can change slightly from the manual as updates roll out, so I'm always holding my breath a little bit!