Get a list of photos that are required. This photographer's brief is a back up so you can say afterwards "you didn't ask me to got those"
Best way to do podium speakers is during the rehearsal, if there is one. Or after they have finished.
Make sure that the slide on the screen is valid and adds to the photo, which means getting to know the technical bods, and/or waiting for the moment.
If it is sponsored make sure that the sponsors logo appears in enough photos
At the last conference I did podium shots needed circa ISO 1000, audience shots ISO 4000 (1/50th sec, f3.5) Podium shots might need less if lit more brightly.
Plenary rooms ISO 1000, f3.2, 1/125 (these were hotel rooms)
I have a full set of f2.8 lenses, under these conditions would have struggled with a 'kit' lens.
Flash bounce it off the ceiling, if at all possible (has to be a proper one, not the on-camera one) - take a set of spare batteries. Try desperately hard not to use it during presentations and if you do have to, use it very sparingly.
Find out how to move the focus point round so that the camera is focussing on what you want it to.
Point and shoot exposure settings will not be the best way to get 'good photos'.
Look out for Fire Exit signs behind people's heads.
I'd be concerned about the daylight rooms, since they will almost certainly have artificial light too. Then it becomes a case of working out at which position the presenter is standing that there will be the lowest clash between artificial light and daylight.
Wear dark clothes and soft soled flat shoes
Wait for the moment. Presenters smiling, laughing, using their hands. Audience laughing, applauding, looking interested, looking at the programme.
Presentations - don't be afraid to repose them just afterwards. "Can I just get you to stand here" and get the group smiling with the award.
Poster competition wtf?
Bear in mind that the conference is ephemeral. Next year there will be another one. Your good photos from this year will be used like a half life decay graph.
Remember: if you don't get 'good photos' he probably won't ask you next year!