How to install and place the camera
The video camera in Phasmophobia requires a few items to function. You need to get it in the truck first, then turn it on, then place it near where you think the ghost resides, then you can check the cameras to see if you spot anything. All of these steps seem simple, but the controls and interface make it harder than it needs to be.
Once you have the camera in your hand, it is the black camera and not the stationary camera, right click or right trigger if using a controller. This will turn it on, as indicated by the red light turning green. You can now set it up and place it somewhere so you can use it to find and identify the ghost. When you think you've narrowed down the location of the ghost (the tutorial will tell you where to go), all you need to do is go into the room and find a spot where the camera can see all or most of the room, usually a corner or table. Later, you can add a tripod to your inventory and use it almost anywhere.
Once you've chosen your spot, just go up and you should see an outline where the camera will be placed if you press F or the left trigger on the controller. You may want to rotate it before placing it, which can be done by clicking with the left mouse button. Once it's at the right angle, just press F or the left trigger to place it at that angle.
So this is how to configure and place the camera in phasmophobia. Now go back to the truck and watch the flow (activate the keyboard to change cameras) to see if you find any ghost spots.