I hear a popping from one of my old double switches. I opened it up to understand the wiring before replacing. I have 4 blacks and 1 red. I have attached pictures. One of the switches controls a light that is controlled by a different switch as well. That switch has a dimmer. The other switch is the only control for another light. How do I go about replacing this? Also, why do I have no ground included?
It looks like you have something like this.
The top switch is the three way and controls the light along with the other dimmer switch. The bottom one is is a single pole that controls a light by itself. You're going to want to buy a switch just like this and wire back the same. As long as you make sure the wires go back in the same positions, you'll be fine.
As someone mentioned, putting some tape around the wires as they are pulled off might help to identify them later. You can get different colors of electrical tape at a hardware store. Also important is to make sure the power is turned off to that switch before working on it to avoid being shocked.
When in doubt, call a professional.