Papers can be assigned to sessions, where a session is a consecutive set of presentations or a set of posters. There is no system-imposed limit on the number of papers in a session. Each paper can be assigned a presentation duration, which is used when per-paper schedules are included in the conference program.
Sessions typically belong to a specific conference and track, but can also be assigned to multiple conferences and tracks.
Coffee breaks, panels, keynotes and other special sessions are created just like regular sessions, with the appropriate session description. The session configuration also has a field for "additional details about the session, such as keynote abstracts." Alternatively, you can create a regular paper entry, probably in a dedicated track, for the keynote or panel, e.g., if you want to attach a PDF file to the keynote session or panel. For in-session breaks, sessions can be configured to have one break after any paper, delaying the start time of the subsequent papers by the break amount.
Each session can be chaired by any number of session chairs, although one or two is typical. If desired, the conference can allow authors or TPC members to volunteer as session chairs. The conference chair can then pick from the list of volunteers, shown sorted by the order in which people signed up and their preference. However, the chair can also choose anybody else to chair a session.
Sessions can be edited by either the conference or the publication chair, via Conference:Sessions. There, you can create sessions, assign papers to sessions (from a paper list), decide who can volunteer as a session chair, or check for scheduling conflicts. Once sessions have been created, you can assign papers to sessions via the link on the Conference:Sessions tab or on each paper page.
Once you have assigned papers to sessions, you can use Conference:Program to generate a conference schedule.
Session chairs can go to Chairing and see a listing of the session they are chairing, including a link to the papers in the session and an email icon to send email to all attendees.