Help with adding cameras as a list

Hi,

Im pretty new to this and am having trouble adding my IP cameras to HA.

I have managed to add one camera using the following code in the config.yaml file…

camera:
- platform: ffmpeg
    name: Outdoor Camera
    input: "RTSP link"

But when i try to add a second camera i get told that the platform line is being duplicated. what do i need to add to create the list of cameras?
This is what i currently have but it is not working…

camera:
  - platform: ffmpeg
    name: Outdoor Camera
    input: "outdoor rtsp link"
  - platform: ffmpeg
    name: Backdoor Camera
    input: "backdoor rtsp link"
  - platform: ffmpeg
    name: Dining Room Camera
    input: dining room rtsp link
  - platform: ffmpeg
    name: Baby Room Camera
    input: "baby room rtsp link"

I realise this is probably a super rookie error but ive been at it a while and cant work it out.
any help is appreciated.

Sam