I’m a little confused by your response (admittedly, that doesn’t take much). Would you please explain it in non-legalese?

Sure.

The lower courts ruled that the President never has immunity from criminal prosecution, for any of his actions. Unlike civil claims, for which most government officials have some immunity (and for which the President has complete immunity for his official actions), the courts held that the President never has any immunity from criminal prosecution for any action - even his official acts.

SCOTUS is likely to reject that. That's not to say that they'll rule that Trump should be found immune for anything at issue in this case - but they probably will push back on the idea that the President could be subject to criminal prosecution for every single act he takes, even the ones that are squarely and inarguably within his official duties. For example, the other day Joe Biden asserted executive privilege over the audio recordings of the investigation into his handling of classified documents - if Trump wins the election, can his DOJ prosecute Biden for conspiracy to obstruct a Congressional investigation because he asserted that privilege? I think SCOTUS is unlikely to adopt a rule that says that even such an anodyne Presidential action can be subject to criminal prosecution.

That doesn't mean Trump gets found immune from prosecution. Most of the factual basis for his prosecution involves private actions as a candidate, not Presidential actions. And I suspect that even a SCOTUS ruling that found that some official Presidential actions were immune from criminal prosecution would have criteria/standards that the US could argue weren't met here. But in all likelihood, that's a remand for further proceedings in the lower court to apply those new criteria/standards, which means no trial before the election - even if the ruling had been handed down in May.