How should I indicate that a button is clickable on mouseover?

1. How to click on a button which is visible only on mouse hover?
2. What is a hover button?

How to click on a button which is visible only on mouse hover?

Do not release the press. Not after the 3 Sec Delay but during it, since it will be visible in that mode. Then After the 3 Sec Delay Release the Mouse Press.

What is a hover button?

Alternatively called a mouseover or mouse hover, hover describes the act of moving a mouse pointer over a clickable object, but not actually clicking the left or right mouse button. For example, when you hover your mouse over any of the links on this page, they should change color, indicating they can be clicked.