In a directions hearing, the member will make sure that the case is on track. That means checking that parties are submitting their affidavits and receiving them from the other party. Depending on the complexity of the case, and the stubbornness of the parties, there could be several hearings.
You should at this stage be preparing affidavits from all your witnesses, and gathering all your evidence. At some point you will be required to share this with the other party.
What does not happen is that parties turn up to the trial hearing with volumes of evidence that no one has seen. At the trial hearing the parties examine the evidence before the member who then makes a decision.
If you are unsure how it works, and you are self represented, I’d recommend going to the tribunal and observing how it works. The hearings and dates are published on the court pages. The tribunal is open to any member of the public.