Marvel movies Netflix order?

I've only seen NetMan on Iron Man 1/2/3, spiderman 1/2/3 & the Amazing Spider one.

I really wanted to watch Spiderman Homecoming, but it seems like a sequel. What should I look for best on netflix to join the Avenger series?

Spider-Man Homecoming is building something up on the first Avengers. So you should have seen before.

Before Homecoming, The First Avenger: Civil War (Captain America 3) would be advantageous as Spider-Man made its first appearance there and the beginning of Homecoming alludes to the events in Civil War.

Otherwise, you can watch the movies in this order.

Here's the order they are from the timeline:

Captain America: The First Avenger
Captain Marvel
Iron Man
The incredible Hulk
Iron Man 2
Thor
Marvel's The Avengers
Iron Man 3
Thor: The Dark Kingdom
The Return of the First Avenger
Guardians of the Galaxy
Guardians of the Galaxy Vol. 2
Avengers: Age of Ultron
Ant-Man
The First Avenger: Civil War
Spider-Man: Homecoming
Doctor Strange
Thor: Day of decision
Black Panther
Avengers: Infinity War
Ant-Man and the Wasp
Avengers: Endgame
Spider-Man: Far from Home