The settings are the easy part, it's timing the explosions that you need to really look out for. First the basics. As others have said, you need a very study tripod and remote trigger (preferably a wired remote). Set your ISO to the lowest clean setting, usually 100 to 200.
The tricky part is framing the scene. You need to be at your location way before the fireworks start, heck even go a couple of day early if you want. You need to know where they'll be coming from and how stuff in the foreground will look (and yes, you most definitely should include the landscape). Take some test shots and use buildings, trees, whatever.....to give you an idea of where to focus for the fireworks later. Take note and remember for later. It's doesn't have to be perfect since you'll probably be shooting at a wide angle and small aperture.
The settings are pretty basic and the camera should be in manual mode. Set your aperture between f/8 to f/16. The only thing you adjust at this point is shutter speed. The easy answer is 'bulb'. Take test shots when its dark, before the fireworks, to see where ambient light becomes a problem. With a small aperture and low ISO, exposure time is going to depend a lot on the intensity and proximity to the explosions. There really is no correct, exact shutter speed. You're trying to capture light trails, which means seconds, not fractions of a second. I prefer to use "bulb" and use a black piece of foamcore. The black foam core is going to act like a shutter. You place it in front of the lens, without touching, to block out the light or to let light in. Trigger the shutter with the remote in bulb and lock it there. This is where timing is everything. Move the foam core away from the lens before the explosion and move it back after the explosion. Let go of the shutter once you're done with the frame. Fireworks don't usually fill up the sky until the finale, so it makes for a more interesting shot with multiple fireworks instead of just one. The rest is chance and experimenting. ND filter will lengthen the exposure time necessary and could underexpose the light trails....or get rid of them entirely. That's not something you want.