I've recently served on a jury for a criminal trial, so I've learned some things about the process that courtroom dramas did not teach me.
One: stacked charges (in this case, 30+) can indicate repeat offenses of the same crime / crimes on separate occasions (usually denoted as separate dates). I do not think this is simply a matter of a single hush money payout (or two, as has been reported in the news). I would not be surprised if there are 10 or more distinct events in play. edit: Note that the jury can render separate verdicts for each charge if desired.
Two: the grand jury merely decides whether there's enough evidence to bring this to trial. The standard of evidence for a grand jury is much lower than the actual trial jury.
Three: this is more theoretical because I'd be surprised if this happens, but the defendant in any criminal proceeding is more than entitled to neither testify on his own behalf, and the defense is not required to call any witnesses to the stand, as the presumption is that Trump is innocent until proven guilty. The burden of proof lies with the prosecution.
Four: I'm going to paraphrase the judge in my case slightly, but "beyond an unreasonable doubt does not mean beyond any possible doubt. There is always going to be some shred of doubt. Beyond an unreasonable doubt means that you have a moral conviction that the defendant committed the alleged crimes."
> it sounds very technical
That's totally expected, as is the case for even the most mundane-seeming laws. The jury is not expected to have a legal background. The judge will instruct them regarding the points of the law (along with definitions of legal terms), and in particular provide criteria that must be met (sometimes with alternatives, e.g. direct vs constructive possession) in order to find the defendant guilty of a crime. https://nycourts.gov/judges/cji/2-PenalLaw/175/175.10.pdf is probably pretty similar to what the jury might expect to see.
As for intent being hard to prove: you are approximately never going to have direct evidence regarding intent. The prosecution can try to establish intent through circumstantial evidence from which the jury can make a reasonable inference. Again, paraphrasing the judge: if you see someone come into the courtroom with wet clothes and shaking water off an umbrella, you can infer that it was raining. Similarly, if the prosecution establishes that Trump took specific actions that could not be reasonably interpreted in a different way other than being made intentionally, or that there were too many of these unlikely occurrences for it to be coincidental, then the jury may use that to establish intent. Further, note that ignorance of the law is not a defense.
You can bet that the prosecution's case is going to center around providing evidence to directly prove those points, regardless of any narrative the lawyers on either side want to spin. At least in our case, we were instructed only to use evidence as presented in exhibits and per witness testimony. Any of the words of the lawyers (questioning, or even opening statements / closing arguments) were not allowed to be considered. The closing arguments are essentially suggestions re: how to view the evidence.
One last note: you cited that a class E felony in NY has a mandatory minimum of 1 year. Even if Trump is convicted of 30 class E felonies, those can be served concurrently, so theoretically the judge could hand down a sentence of 1 year prison time if he so desired. I think that's highly unlikely, but it is possible.