I live in a sun home trailer and the light really got on my nerves because when you flip the switch the light takes a minute to kick on and when it kicks on it is dim but it flips back and forth from dim to bright over and over for a while then it stays bright until you turn it off. So I decided to try and fix it myself. Nothing was wrong with the light itself, but I went into the light switch to see what's up and I thought "let me try to connect this weird copper wire (that's connected to nothing, it's just in there) to the screw holding the wire from the side of the switch". I flipped the switch on on and all I heard was a small buzzing sound, the light didn't turn on and the TV cuts off. I instantly cut the switch and disconnected the copper wire and now now nothing in my room works. No outlets or the switch works but everything else in the house works but this room. Help me out - I'm lost. I tried doing the fuse box it didn't work.
I hate to put it this way, but you are in way over your skill level. I highly recommend getting a professional electrician to help at this point.
You connected the ground wire that to the switched hot. When you turned on the switch, you shorted the circuit. That should have caused a fuse to blow or a breaker to trip. Based on "I tried doing the fuse box it didn't work.", you either have not found the correct fuse or breaker, or some part of the electrical wiring in the room (possibly at the switch, possibly at an outlet) burned up (literally) and broke the circuit.
Hopefully a fuse or breaker did trip - if not then the safety of your fuses/breakers is questionable. But even if you find the fuse (and replace it) or breaker (and reset it), there is definitely a possibility of damage due to arcing in any/all of the devices on that circuit (switch, receptacles, any wire junctions).
Now for the educational part: Most circuits have a hot wire, a neutral wire and a ground wire. Normally (there are exceptions in various situations), the hot wire is black or another color besides white, gray or green; the neutral wire is white or gray; and the ground wire is green or bare copper. There are a number of situations where the ground wire is not connected - particularly switches. In those situations, there still should not be any loose ground wires - they should be connected to each other, to metal boxes or capped - they should not be floating around loose as you found. Simply connecting wires "because it is there" doesn't usually end very well.
As for your specific original problem, my hunch is you have a fluorescent light that needs a new ballast and/or starter and/or bulb.
Not an electrician, or an expert, but I believe the copper wire you're talking about is a grounding wire. In a home, it's typically attached between the switches ground post and the metal switch box enclosure. The enclosure is then grounded inside the wall. I am not sure how a trailer would be grounded, perhaps by a grounding post that you place in the earth after travelling?
I'm not sure what kind of damage you may have caused by connecting to Neutral or Hot, but you likely did do some damage either to your fuse/breaker or to your appliances. I would start by eliminating the appliances by moving them to a room that is still working.
You should definitely leave the grounding copper wire attached to the metal switch box if it was attached previously.
As others mentioned, I would seek out the help of an electrician. You have likely damaged the circuit.
This is a wiring fault, specifically, an arc fault. It is a firestarter.
Really, given your level of skill and confidence, and the fact that you are literate, I suggest getting a well-rounded basic primer on the art of electrical work. Google won't provide this, hit a library and try several of their books on electrical until you find one that seems like it speaks to you.
Then move through the house, looking at every box (particularly those which lose power when the fuse is pulled). Look for anything that's not right. If you have backstab connections, change them to side screws. If a socket or switch looks damaged or worn out, change it.
When you do this at one location, the problems will just go away.