Transcription doesn't show the correct speaker

Hello!  

I'm learning about how to create transcriptions from my client meetings.  I'm excited to use this feature, but in the first meeting I tried it out on, the speaker's weren't correct.  The meeting was named for me and one of the clients, but there were two clients at the meeting.  Whenever either of the client's spoke, the transcription labeled the speaker as the name from the title of the meeting.  
I'm not worried about making changes for that meeting, but for future meetings, how do I set up the correct speakers so that the transcription is matching the text to the person speaking?  

Thanks!