When you’re on a call on your analog phone, you can add another person to the call and create a conference. That way, you don’t have to make a second call: all three of you can discuss as needed.
You can talk with several people in a single call.
While on an active call, perform a hook flash.
This puts the call on hold and you hear dial tone.
Dial a second number and wait until that person answers.
To create the conference, perform a hook flash.
You are now in a conference with both persons.