There are a few key procedures to keep in mind when preparing for and playing an individual session.
Most sessions begin with the party assembled in a relatively safe area in the campaign world (a town, camp, or well guarded space). It is presumed that the characters assembled have some interest in adventuring with one another. Some sessions may begin in media res if the attendees ended a previous session on a cliffhanger or in a particularly dangerous situation (deep within a dungeon).
In order to play a specific character for the session, it must be feasible for them to be present at the starting location. If they left off in a different part of the world or doing something long-term (like magical research), you are encouraged to choose (or create) a different character.
To the degree possible, 'town stuff' should be done between sessions with the Referee via Discord. This will mitigate the more mundane bits in the limited time available to play. The Referee may also allow a few minutes to handle any off-screen affairs at the table before the session begins. If you show up late, you have missed your opportunity and will need to wait until next time.
After any necessary house-keeping is completed, the party is expected to get into the action right away. Ideally, the night's adventure has already been discussed in order to maximize the time at the table.
The players and Referee will agree on how long they will play the session. As the end of the session draws near, the Referee will inform/coach the players that they are running out of time, possibly advising if certain courses of action would be too time-consuming. The players should make a reasonable effort to return to safety before the agreed upon ending time if they wish to have the flexibility to play their characters in the next session.
If the party wishes to press on or not return to safety by the end of the session, they may do so at their option. These situations will be handled on a case-by-case basis, but most often will require the same attendees to assemble for a second session to pick up where they left off. Their characters will be unavailable for play in any following sessions until this occurs.