There is a specific use to every slider, so let's go over them one at a time.

So here is an image of the node group:

First we have the Tile Settings. Its settings include:

• Color - Adjusts the color of the tiles
• Scale - Adjusts the size of the tiles
• Bevel - Adjusts the bevel on the edge of the tile (very little difference)
• Variation - Adjusts the amount of variation in a random pattern on the tiles (adjusts the value only, hue and saturation are not changed)

Next, we have Mortar. Its settings are as follows:

• Color - Adjusts the color of the mortar
• Thickness - Adjusts the width of the cracks (mortar) between the tiles (does not apply to broken cracks)
• Displacement - Adjusts the depth of the mortar.

After Mortar, we have the settings for Damage (Please note, the damage section pertains to small scuffs in the tile, not the cracks). They are the following:

• Strength - Adjusts the strength of the damage
• Scale - Adjusts the size of the scuffs (useful to make the scuffs look more like pores in some instances)
• Detail - Adjusts the detail in the damage (useful to make the damage look smooth or rough)

Up next, we have Grunge. Its settings are:

• Amount - Adjusts how thick the grunge is
• Scale - Adjusts the size of the grunge
• Thickness - Adjusts how thick the grunge is (similar to amount, but adjusts it differently)
• Crease Amount - Adjusts how much more grunge is added in sharp creases
• Crease Contrast - Adjusts the contrast between creases and flat areas (only in respect to the grunge, it effects nothing else)

And finally we have Cracks. Its settings are the following:

• Cracked Tiles - Adjusts how many tiles are cracked (works on percentage, so 0.0 = 0%, 0.5 = 50%, and 1.0 = 100%)
• Cracks Color - Adjusts how much darker the cracks are (0 is none, and 1 is black)
• Scale - Adjusts the size of the cracks
• Thickness - Adjusts how wide the cracks are
• Noise Scale - Adjusts how large the noise is 
• Noise Detail - Adjusts how rough the noise is
• Noise Amount - Adjusts how much noise there is (0 = clean breaks, like glass, 1 = rough breaks like rock)
• Worn Edges Threshold - Adjusts how far in the wear around the cracks goes
• Worn Edges Amount - Adjusts how much wear is around the cracks (if the tile was just broken, then it would be set to 0, however, if it was broken long ago, 1 might look better)

And that's all of them. Some other important things to know...

1. The model MUST be UV Unwrapped in order for the tiles to work. The tiles themselves rely on UV's, but nothing else does (grunge, cracks, mortar, etc).
2. If the grunge, cracks, scuffs, etc. looks like they're squashed, it's because you need to apply the scale (and preferably the rotation as well).
3. The shader is procedural, so it does render a bit slower. My suggestion, if you're having trouble with render speeds is, to get the best look you can, and then bake the textures, so that you can have the best of both worlds. There are some excellent baking tutorials on YouTube if you don't know how to bake already.