if CAS works the same as most tribunals be it for sport (CAS is a sporting tribunal not just for football) so nothing todo with UEFA.
First Stage should be a pre meeting , were the court will say which evidence is reelevate which is not , this is were they find out if the emails are reelevate , they will listen to all arguments why and why not it should be in or out . these are short as your not proving your case at the pre meeting .
Then it goes to the main event , were the panel will play devils advocate , both sides need to prove there case not just us and only with the evidence agreed at pre meeting ,
hope this is of some help