What should one do if they find one hundred Egyptian pounds at the entrance of their workplace, it doesn't belong to any of the employees, and it is difficult to reach its owner?

If the amount you found is something commonly sought after by people, then you must announce it for a year. If its owner does not come forward, it becomes yours. However, if it is a small amount that people usually do not care about, then you may own it without announcing it.

And if the money you found is in a place where it is difficult to find its owner, such as a desert road, then it is permissible to give it as charity or to hand it over to the judge to dispose of it in accordance with Islamic law.