A computer network is defined as a system that connects two or more computing devices for transmitting and sharing information.
A computer network is like a highway.
There is traffic when driving on a highway, as many individuals are navigating the roads to get from one place to another.
In some cases you drive on the highway to get from one city to another. Maybe you need to drop off a package. Maybe you need to tell your friend something in person.
The network of highways allows you to get from one location to another in an organized manner.
A computer network refers to the interconnected nature of computing devices communicating with one another.
Not knowing what a computer network is will not inhibit your ability to start a tech company. You should know what a computer network is, that by even reading this right now that means you have accessed a computer network, but outside of the basic definition this won't impact your roadmap.
It is important to know if you want your product/website/app to be online and available to others from other devices, meaning it is on a computer network, but you don't need to know the technical terms behind it. You will be a-okay so long as you know you want your product accessible.