At the beginning of a session, the lead coach (the Host) enters in the boats and the session details (date and length). After this, the other coaches can join the session. The session information will be transferred to each coach's phone. You all press 'ready' and off you go. Each coach (one at the start, finish and throughout the course if wanted) will log when the boats pass them via the app. When all the coaches reconvene, you will be able to automatically share the times and assess the scores.
You can also save the trial details and go direct to a re-run.
Lastly, if you don't have help to run the time trial, this app still accommodates. Just click 'ready' if no one has joined your session, and you will be given the option to run the session by yourself.
P.S. The trash-can seen in last screenshot is just in case you want to stop recording a time for that crew.