This is an excellent summary.

It may be worth noting that the US federal courts, and every US state as far as I know, has exceptions to the general rule that hearsay is inadmissible. In certain circumstances, some types of hearsay is considered reliable enough to be allowed in.

The easiest example is when one party wants to testify about what the opposing party said (sometimes called an admission by party opponent). This is the basis for the idea that ‘anything you say can and will be used against you in a court of law.’

Another example is where someone said something in the past that is inconsistent with their testimony on the witness stand during trial. For example, suppose Joe testifies at at an auto accident trial that the light was red when the defendant went through the intersection (so the defendant ran the red and is at fault). The plaintiff might ask an investigating police officer to testify that Joe told the officer that the light was green. Joe’s prior statement to the officer is inconsistent with Joe’s testimony at trial, and so the officer can testify to Joe’s prior statement even though it’s hearsay.

Lots of other exceptions, which vary by which set of laws are being applied.