Stock values relationship with investor capital?

I dont know economics so break it down like im just a teenager.

If an entity invests in a company or startup, the stock goes up. If the company uses that investment money to pay employees, does the stock value go down, and if not, why?

Im trying to grasp some concepts on capital and stocks that just dont seem to be clicking. I understand an evaluation of a company and its finaces can give something value and that the stock market has a lot of variables including human emotions, but changes in stock value due to investment seem to have my brain overloading.