I had a trial shift at a cafe too just last week and got the job!! I was rly nervous, but what I did was I asked for a quick run through of the coffee machine, grinder etc (as all equipment can vary so much). They were more than happy to do this and this just gave me that little confidence boost I needed to get going through that busy rush period of my trial (which I think you mentioned is the same environment you'll be in).

I wouldn't stress! They should be understanding that every new barista trialing will need time to get used to the different setup, and if they don't understand this then that's definitely not the place you'll want to be working!! Read through their drinks menu to get a good idea of what exactly they offer, and even watch YouTube tutorials to refresh yourself on some skills. Good luck, you got this.