How do you hook up a bunch of Tvs together to make one big TV like used see in old 80s movies?

You would need a video switcher (also called a video matrix) to connect a bunch of TVs together. A video switcher is a device that allows you to connect multiple video sources to a single TV or projector

1) Connect the output of each TV to an input of the video switcher.

2) Connect the output of the video switcher to a TV or projector.

3) Use the video switcher to select the video source that you want to display on the TV or projector.

By doing this, you can create a "video wall" of TVs that all show the same video content.

If you want to create a "big TV" that is made up of multiple TVs, you will need to use a video processor in addition to the video switcher. A video processor is a device that can take the output of multiple TVs and combine them into a single image that can be displayed on a large TV or projector.