I assemble the Switch in a slightly Different order then some, but it works Best for Me.
I put the 510 Pin/Insulator in 1st. Holding it in place by putting an Atomizer in the 510 threading. Then I put the Disk Insulator on the Bottle side of the 510 Pin.
Now I put the Contact Screw in the Long Side of the Transfer Bar/Spring and it is held in place by that Little Black O-Ring.
Then I place the 2nd Disk Insulator over the Switch Side Hole and put the Transfer Bar/Contact Screw assembly on the Bottle Side of the 510 Pin. Then I screw on the Bottle till it is just Finger Tight.
To get the Contact Screw centered on the Switch Hole, so you can start threading the Fire Button onto the Contact Screw, you need to Push Down on the transfer bar hump slightly. Now you can screw on the Fire Button on a few times which will hold Everything in place.
Now Turn the Fire Button until the Line on it is Parallel with the Long Side of the Mod's Top Half. And then Gently Push the Fire Button all the way Down.
Now snug up the Contact Screw with a Flat Screw Driver.
At this point everything is Basically Assembled. But Not fully tightened. And you can test the Fire Button throw. And the Fire On/Off.
If everything feels Good, then Remove the Atomizer from the 510 Threading and with a Small Flat Screw Driver, GENTLY Tighten the 510 Pin while holding the Bottle. The 510 Pin Doesn't need to be Super Tight. Just Snug.
Now do the Same Thing for the Contact Screw. Tighten it till it feels Snug. And you feel that Black O-Ring Compressing. It Doesn't need to be Super Tight.
Give it one last Fire - On/Off Check and you should be Good To Go.
Hope this Helps. And if it does, you could Copy n' Past it to something Printable, then print it out and stick a copy of it in your Coppervape Box for future reference.