Dimmer switch back to normal switch
You see how the new switch has 4 terminals: C for common, 1, a covered-up 2 that you won't be using, and "Loop" which appears to be merely for convenient splicing.

You also notice the old switch has 4 terminals that appear to be in the same position. I will assume they are labeled the same.  

So.  The two red wires from the wall that went to "1" on the old switch.  They need to to "1" on the new switch.   Easy peasy.

The one red wire that went from "Loop" on the old switch needs to go to "C" on the new switch.  

And we're done.   

Oh wait.  You also messed with the black wires.  That was not constructive since they never went to the old switch in the first place.  Put them back exactly the way you found them.   



In the future, if you are replacing something, and you see wires that do not go to the thing you are replacing, leave them alone.  They are not part of your project.   You made your situation worse by messing about with those black wires.  We see this all the time; at extremes one fellow wanted to change a light fixture and instead of touching the 2 wires that went to the fixture, dismantled all 12 wires in the box.  He knocked out power to half his apartment and his neighbor's lights, and wound up having to throw himself at the mercy of his landlord's electrician, that wasn't cheap!   I call this "trying to learn electrical by dismantling your house".  I recommend a book.  

Now if you're wondering what is the deal with those color codes, look at the cables available for sale at your home improvement store.  Now, your working theory is that the color codes are there to help you hook up the wires, and therefore they designate the function/purpose of the wires.  There would need to be a variety of color combinations offered buy shops, so you could use black/red for power, black/blue for lamp, red/blue for switch loops, etc. But no.  The shops only sell red/black. 

With all cables looking identical, position is everything.  Position gives us the information of what the various wires do.  That's why it matters which two red wires were together in the previous config.  That is why the guy I mentioned got in so much trouble.   

Myself, I either work in conduit or color-code my wires with tape. So in my boxes, yes, you just join all purple wires. But that is because I go out of my way to make it so.  It's not automatic.