Need Help/advice installing a 3 way dimmer switch

Cap y immediate guess is the red is hot, switched between the two lights and you really don't hafta know about the grounding. However, not all lights will work on a dimmer

Edited to remark, but I wonder if that new switch doesn't have a neutral terminal (which its presumed semiconductors might need), in which case of course I'd'v been wrong, which is gonna make it necessary for you to identify other wires thereabout

How involved it all gets

Thanks for the reply! Sorry it took me so long to respond, I was at work. I haven't gotten back to it yet, but the more diagrams I've looked at, I've come to think that the red is what they chose to connect the switches, so I'm thinking it's a traveler, as well as the black that accompanies it. which leaves that other black as the common wire. As for the ground, I think since it's a two switch system, whomever wired it originally must have grounded it in the other switch, and just let that be the ground for that switch system. I can't think of a reason why I can't hook in my green ground wire to the bare ground in that switch though, right?

Oh gosh cap, I'd need diagrams. But maybe we'll hear from Eng or Man, or one of the other technics

I am having a very similar issue trying to update a ceiling light fixture with a 3 way dimmer switch. I also have 2 bundled white wires that were connected to the previous light fixture. The old wiring wasn't one black wire and one white like my new fixture. I am unsure if the new fixture is compatible, or if it matters which existing wires to connect the new black and white wires to. I wish you could attach your pictures. I'm sure mine are the same or similar.

Cap,
You have a three way dimmer system which is going to consist of two switches yea'. Each of your ol switches shood look like this; bare grounds/green wire nutted and on switch ground, white wires nutted in a joint not connected to the switch, then on your tree way switch you have a common terminal (one switch containing power in and the other switch common containing power out to the light), then you have two travelers usually on the bottom of each switch that let power back and forth between the switches. The travelers and power in and out tend to be one black on the common and a blackNred for travelers, tho this can change.
So basically you wanna get your instructions on the back of the dimmer box and look which wires to connect your dimmer to, it has a diagram which is not rocket science. If your dimmer switch is basic and does not have a built in led you probably wont need to worry about connecting anything to the white wires, just make sure you ground the switch.
Also you are only going to want to put one dimmer switch in, if you put wo dimmer switches together your light wont turn on. So find out which switch is your power in on the common and put it there. You may be able to put the dimmer on the power out common if that is a more desired location but i dont know if that works I have always been told to do the other. You may have to break the metal tabs on the dimmer switch front to get it to fit in the box also.