Conference calls explained?

[Keeks90]

Hi, so I've been using 3xc as a way for my partner to ring me. All I know is how to answer calls. So my question is how do you know if you have been merged into a conference call and a couple of phone calls were really weird out of no where music started playing like I was as on hold rang my work phone on the 3xc app and put it on hold and it was the same music. Also I had accidentally tapped the screen and it just came up with 'Private Number 2' on the screen. Can post a pic of it. When you download the log report would it show the extensions?