Have you decided what to wear? Do you need your hair done? Looking fabulous in itself gives confidence, I know it's shallow, but if we feel we look good it can often help with how we portray ourselves to to others.
In addition remember he clearly doesn't want to do it either, he has delayed in responding and had his solicitor try to get you not to proceed with it. He pretty much has to do it or it will look bad to a court, so you've got him by the short and curlies here.
Remember he doesn't know you're shitting it. He will be thinking fuck me I can't believe she wants to do this. He thinks you want to.
In addition use the time wisely to prepare yourself mentally not to lose it or show anger, don't be calling her a dirty skank, or him a fat holidaying wanker or whatever mid mediation. You can say what you want when it's done, but prepare yourself to mentally bite your tongue in there or it will make you look bad and derail it.
The objective is to get the financial settlement agreed not turn it into a slanging match, because he may match you insult for insult, or simply leave mid mediation saying you became abusive.
So look good, be prepared, bite away any insults you find yourself thinking of, quietly go for the jugular,,,😁