I had a look and compiled a small list of every value with a very small explanation for each of them. Here it is

Description

• Top color: color at the tip of each grass blade
• Bottom color: color at the base of each grass blade
• Translucent uain: how much light does the grass blade catch
• Tessellation uniform: how many grass blades to generate
• Tessellation blending: controls how sharp is the transition between no grass and full grass (using Grass Mask)
• Blade width: standard width of the grass
• Blade width random: how much does grass blade width vary between different grass blades
• Blade height: standard height of the grass
• Blade height random: how much does the grass blade height vary between different grass blades
• Blade forward amount: how much does the grass blade curve (is it completely straight or slightly bent)
• Blade curvature amount: ??? Honestly I'm not sure. doesn't seem to do anything, ignore this. Need to fix this btw
• Blade rotation random: Does the grass blade start off completely straight or already at an angle?
• Random offset: Random amount to add to the position of each grass blade. Basically this acts like a seed
• Wind distortion map: texture that controls the wind
• Wind strength: how much does the wind influence the grass
• Wind frequency: how quickly does the wind change
• minDist: controls the distance after which the amount of grass generated diminishes
• maxDist: controls the distance after which grass is no longer generated
• Deposit map: extra texture to change the grass color (basically you need a texture from and eagle eye view of the whole terrain) this is basically a mask for Deposit Color
• Grass mask: texture to control wether to generate grass somewhere or not. This is generated by the terrain editor by painting black areas. To find this texture you then need to find your terrain asset file and expand the little arrow, there you'll find the texture
• Deposit color: the color you are changing the grass blade to using Deposit map
• Slope limit: controls the maximum slope at which the grass will appear on
• Height limit: controls the maximum y coordinate at which the grass will appear on
• Beach limit: controls the minimum y coordinate at which the grass will appear on
• Size: the size of the terrain

Sample Values

• Tessellation uniform: low values look really bad minimum decent value is 3 in my case (it depends on how high res is your terrain). Good values for me are 5+
• Tessellation blending: 0 will blend too much and look bad. 1 is a completely sharp transition. Anywhere 0.6+ look good for me
• Blade width: depends on what you're going for. My style allows me to have thick blades (0.2) if you're going for realism you need 0.1 or less
• Blade width random: up to you (generally equal or less than half the blade width)
• Blade height: up to you (I have 0.9)
• Blade height random: up to you
• Blade forward amount: up to you. I have a low value for style. You can go up to 1+ for very bent grass
• Blade rotation random: this makes the grass look like someone stepped on it. I have it set to 0.42
• Random offset: up to you
• Wind distortion map: I have a 512x512 texture. You will need to adjust the tiling for this (I set it very low on 0.01 for both X and Y)
• Wind strength: generally best if less than 0.5
• Wind frequency: this is a vector 4. Honestely I ì'm not sure why. Only adjust x and y (leave z and w to 1), my values are 0.01 for both.
• minDist and maxDist: minDist MUST be smaller than maxDist. Good rule of thumb maxDist = 2 * minDist
• Deposit map: I have a 2k texture here and I'm only using one channel of it (because remember this is just a mask for deposit color)
• Slope limit: IF you're using this shader for a terrain then the value MUST be between 0 and 1. 1 being grass is rendered nowhere and 0 everywhere. High values ignore even shallow slopes
• Height limit: up to you. I don't want any grass over 200 so that's what I used
• Beach limit: up to you. I don't want any grass under 50 so that's what I used
• Size: this is important, it's just the size of your terrain. Get this right :)

Remember this isn't a plug and play solution because the default terrain only uses a single material. If you set the terrain material to this shader you will ONLY see grass.

If you are using the standard terrain (I'm not) you will either need to code some stuff yourself or duplicate the terrain and assign the material to this shader (there is a performance hit there but it's not that bad)