I guess you weren't there that day. Oh well. The method is actually surprisingly easy. All she has to do is push Trump to give details, then follow up by explaining the blatant problems with those details.
Yeah, that's one way, but again, Trump can simply shrug away policy question by repeating meaningless platitudes and just shove a one or two solutions to some policy questions.
The danger for Hillary there, is that she spends too much time trying to bait him on policy questions and I'm not too sure Trump will completely flounder.
The time constraints (and the stumbles that comes with this for Trump), the lack of an audience to feed off and a disrespect for Hillary are, IMO, the biggest tools at her disposal, couple with a strong performance from her.
Honestly, it won't matter, in the end, what Trump does, in part because of low expectations for him. HIllary has to concentrate on giving her message and at the same time, be prepared for Trump, but she shouldn't let him be her mission.