ITS BEEN ON MY MIND

I’ve been wondering some things so here they are…
In the Garden of Eden Eve and Adam gave in to temptation from a serpent which in church has been identified as the devil or Satan.
However I also have been informed that Satan is a fallen angel…hmmm.
If this is true I am confused…if Satan was a angel…we all have been told that an angel is a human brought to heaven to serve God…does that mean there were people on earth before Adam and Eve?