How do I establish an open connection to an open web browser in C#?

[PlausiblyDamp]

On a broader view, will all this mean I will have to make a web browser from scratch?

I do not think so. Here is the bottom line. I am using selenium commands. Selenium is used for software testing. So there must be some way to attack a C# program to an actively open chrome web browser and interact with it. How do I do that?

Is it better to use a different browser other than Chrome? How would I do that in C# code?

Or you could try using the API like I already suggested. Automating access to LinkedIn is against their T&Cs and they are probably making it harder to do this to prevent people doing exactly what you are trying to do. Creating an entire web browser from scratch is a massive undertaking, doing this to circumvent the current system seems overkill; especially as they could change the system at any point and completely render your custom browser useless in this regard.

The API exists as a way to get at information in a supported way, it is going to be a lot easier to use a supported method than create a web browser from scratch.