Nobody really knows. As it happens with ancient cultures, we don't have specific details.

I don't know of any form of musical notation in Ancient Egypt, that puts us in a pre-historic situation in musical terms. As far as I know the only notation they had was the one brought by the Greeks (a lot of things happened before that), and we can't be certain about how Greek music sounded because we have no idea about their actual musical practice (having some notation does not solve the whole problem). Are there surviving Greek notations of Egyptian music? How would the Egyptians use the Greek notation? Did they adopt some aspects of Greek musical practice to use that notation? I have no idea, I don't even know if we have any sources on that...

As it's usual with many cultures, we find depictions of musical actions in art. We find depictions of people who are performing some kind of music, playing instruments and singing. I don't know if we have actual surviving musical instruments or fragments of them, but the depictions show string instruments, wind instruments, and percussion instruments. It looks like some people could have been clapping.

Music was, apparently, present in different settings (including religious and public events, that kind of music was probably very organized). We find the religious figures of Hathor (joy, feminity, motherhood) and Bes (defensor of good things) related to music (so apparently music was associated with good things). Music was apparently part of their religious life.

So, they had a decent number of different musical instruments and music was present in different parts of their lives. They could have some rather organized forms of music for the public events (speculation, but organized music tends to happen when you have organized events).

Other than that, who knows. Ancient Egypt was very long ago, and that term covers a lot of time and a significant area. And we don't have much to work with to get specific details.

What is usually played in movies and what not to give an "Ancient Egypt atmosphere" is a mix of a lot of things that are kind of foreign to us Westerners, it's meant to sound exotic. They some times combine elements of things that are probably very old (instruments and tunings), but there's no way to know how close or far the result is from what was going on back then. Some times they just go for things closer to Arabic music.

We can try to make instruments that match the surviving depictions, but everything we manage to play will be speculation.