Put R13 insulation on one side, the bottom and the back. Don't put in too much or too little, just a single sheet on opposing sides. If you haven't braced well, cut some 1x2's so that they fit snug across front to back and side to side. Glue a few of those in so that the cabinet is solid. If it isn't braced well, it will sound throaty in the lower midrange.

About wiring, I'd be happy to go through that with you. The tweeter should be connected to the wire with the block of parts on one end. The block of parts connects to the crossover, and you'll want to lay it on the R13 as a vibration isolation pad. You can also use a silicon rubber and fasten it to the nearest coil and the 22uF cap on the PCB. Goop that stuff up to make a little rubber bumper and press the resistor block into it. But first, let's make sure it's wired right. The tin lead goes to the (+) lead on the tweeter and (T+) on the crossover. Copper goes to (-). Make sure the spade lugs are snug, but not so tight they're impossible to push on. You can break lugs by forcing them too much.

The midwoofer is easy. Use the straight wire and connect (+) on the woofer to (W+) on the crossover, and woofer (-) to crossover (W-). The Zobel is the part with the big aluminum resistor block and the capacitor. It only has two leads, connect one to the woofer's (-) lead and the other to the woofer's (+) lead. Again, make sure the spade lugs are tight but not too much. The Delta 15 is really easy to break spade lugs on that little connector panel. The connector panel isn't much more than cardboard, so it's easy to snap. Take it easy on those, and support them as you press them on.

The connector panel red post connects with a straight wire to the crossover's (+) input, and black to (-). Use the red post to connect to your amplifier's positive connection. The way you can tell if you're phased wrong, is to face the two speakers together and play some music with bass. If they're phased wrong, you'll still hear sound but not as much bass. Try it sometime.

Let me know if you have any trouble.