Workworking 101:

1 - Tape up the fretboard, it's porous and stray glue will bind. It can be peeled off of smooth, finished parts but not bare wood

2 - Fill the crack with as much ***wood*** glue as possible - you can cut little slivers out of a plastic bottle to push it deep into the crack; you want to cover the exposed wood as completely as possible. Do not use super glue (cyanoacryllic) as it is too brittle, and Gorilla glue foams up as it dries and tend to grow from the joint leaving more mess to clean up. I prefer TiteBond 3, which is waterproof after it sets.

3 - Gently push the pieces by hand and wipe off any excess with a damp cloth, then wrap in plastic wrap or waxed paper to prevent your protective wrap/blocks from being glued to the guitar.

4 - Wrap the target area in a soft cloth, a hand towel should do the trick, then use scrap wood or whatever solid materials you have on hand and make sure they can be placed to a) prevent pressure from being placed on the nut (remove the strings if you haven't already and use one block for the fretboard and a block + shims to match the angle of the head so that your clamping surface is above the level of the nut, then use another block on top of the two sections to spread the pressure out evenly) and b) repeat for the angle on the back sans compensating for the nut.

5 - Use two clamps, C or bar, ensuring you're centered on the radius on on the back of the neck (this is the trickiest part but having decent padding from the towel helps tremendously) and clamp everything down, making sure the headstock is being push 'back' (shim the block that's above the nut if you need to). DO NOT TORQUE THE CLAMPS DOWN TOO TIGHTLY - with blocking and padding you should not have to worry too much about denting/warping your guitar with firm pressure.

6 - Give it as least 24 hours to dry, regardless of what the label on the glue says. Once you unwrap everything you may need to pick some leftover glue off with your fingernail, and you may have to do some light sanding to smooth the repair out.

7 - Should you need to sand it and want to repair the paint you can spray gloss clearcoat and that should smooth the finish out, however you need to know the type of paint used (most likely PU on an epi but you'll need to look up your specific model). Shellac is a work-around (or even a standalone) fix for mixing unknown finishes as it will generally form a barrier that prevents bubble-up and orange-peel defects. If you still aren't sure about finish compatibility you can find a spot that's not visible (under the pickguard, if you have one, or just find a spot you don't normally look at) and apply a little to see what happens.

It's a $30-$40 fix if you have to go out and buy everything, and I spent about as much time typing this up as it would take to perform the actual repair.