How can I put the camera in a custom position?

You should use

local camera = workspace.CurrentCamera
local cframe = CFrame.new(0, 10, 0)
camera.CFrame = cframe

It moves the camera to 0, 10, 0, but you can change it to whatever you like.

You should also look for info about CFrame.Angles to turn the camera where you want.

This method is known as the Cinema method, wherever you place a brick, the Camera will look in said direction. First, you want a LocalScript, reminder that the Camera or CurrentCamera can only be accessed through this type is Script. Put this in StarterPlayerScripts.

Follow this example

local Cam = workspace.CurrentCamera --// This must be referenced as ‘CurrentCamera’.
local CamPart = workspace:WaitForChild(“CamPart”) --// References to the Part to view from.

After referencing everything, we move to configuration.

Cam.CameraSubject = CamPart --// ‘CameraSubject’ is the part the Camera follows.
Cam.CameraType = Enum.CameraType.Scriptable --// Scriptable makes the Camera freeze.

After configuring, we set the look direction

Can.CoordinateFrame = CFrame.new(position) --// Set’s a custom position from the CamPart.
Cam.Focus = CFrame.new(direction) --// Set’s the direction of where Cam will look.

This is the end, just add everything together and you have a proper Camera Manipulation Script

Hope this helps, if so, press accept answer and upvote! Good Luck