I'll do my best from one Christian perspective but they are tricky questions.other people will have a different view.
Timeline:
God ( trinity of God the Father, God the Son and God the Holy Spirit) existed before time/the world.
He/they created everything from nothing.
The creation story tells us about who created it not how. (Science will sort that bit out) It was written to contrast the other stories and cultures around at the time. For example some religions worshiped the sun as a god and the Christian/Jewish story is that the sun is not a god but a big light put there by the Christian god)
some Christians believe it was literally 6 days and the world is only 6000 years old. (They calculate from the somebody begat another when they were so many years old) They tend not to believe in evolution. Others believe the world was created by God but see the story as more symbolic and evolution was part of the process and dinosaurs were part of that.
I think 6 day creationists believe that the world was created with dinosaur fossils ready fossilized.
As for people who died before Jesus...
Many Christians believe that the death of Jesus was once for all time. Sort of backdated. Those that went before were saved by faith in God. There's a whole long list in the New Testament of old Testament characters having been saved by faith...(I think the book of Hebrews chapter 10 or 11 but I've not checked. )
There is a belief that God revealed himself bit by bit through history . That he foretold the birth of Jesus throughout the old testament. He used temporary means of sacrifices to symbolise the once for all time sacrifice of Jesus and as a stand in until that happened.
Christianity nowadays usually sees itself as starting from the creation of the world and diverging from Judaism when Jesus came along... rather than beginning with Jesus.
Some Christians interpret the Bible more literally than others or that it doesn't matter that it was written in a different culture and language in different styles of literature.
Also, as with anything involving humans, people will use it for their own ends and pick bits out of context to suit themselves and gain power over or abuse others.