Discussions are a great feature designed to enable breakout conversations that don't clutter the rest of your class channel. These are breakout spaces that can be for specific topics, such as a video or article, online office hours, or group work.
Discussions also help keep the channel organized by keeping conversations contained and bracketed appropriately as well as being searchable later.
Discussions in your channel can automatically be seen and accessed by everyone in that channel, so you don't need to "invite" all of your students individually. A list of all the discussions in a channel can be found by clicking on the three dots in the upper right-hand corner of the channel and selecting "Discussions" from the drop-down menu.
See Creating a Discussion to get started!