here it is in a nut shell.

got this off a website:
Camber
Camber is the amount of tilt measured between the top and bottom of a tire in reference to a vertical plane orientated in the same direction as the vehicles forward motion. The camber of the wheel is typically measured in degrees of tilt. A tire that is tilted in at the top and out at the bottom is said to have negative camber. The farther it angles out at the bottom the greater the amount of negative camber. To obtain positive camber, the top of the tire would be positioned farther out than the bottom.
The reason for having camber in your front end is as follows. As an ATV starts to initiate a turn at speed, the weight of the vehicle in motion (inertia) begins to compress the suspension and the quad starts to dive. The force generated at the contact area between the tire and the ground begins to flex the bottom of the tire under the machine. The flex of the tire as well as the change in attitude of the machine, tries to reduce the amount of negative camber.
A tires greatest traction is achieved when the maximum amount of tread is in contact with the ground. Maximum front tire traction is crucial when trying to turn the vehicle. Therefore, negative camber is added to the front tires to compensate for the cornering forces that act on the vehicle during a turn. The amount of compensation required depends on a number of factors such as the amount of suspension travel, the bike geometry and the type of terrain you plan to ride on. Below is a recommended starting point for your camber adjustment.
Motocross: 4.5 degrees
Cross Country: 4.5 degrees
Sand Dunning: 2 - 4 degrees
Desert Racing: 2 – 4 degrees
Recreational Riding: 1 - 3 degrees
Caster
If an imaginary line were to be drawn that passes thru the center of both the upper and lower heim joints, the angle that would be created between that imaginary line and a vertical plane constructed thru the spindle axle is referred to as Caster. If the upper heim joint is farther forward than the lower heim joint, it is said to have negative caster. If the upper heim joint is farther to the rear of the lower heim joint, it is said to have positive caster. The greater the amount of positive caster, the more stable the ATV will be at speed. The less positive caster the vehicle has, the easier it will steer and quicker it will turn. Below is the recommended starting point for your caster adjustment (not available on most Factory Pro arms excluding those manufactured for both Kawasaki and Suzuki)
Motocross: 4.5 degrees
Cross Country: 4.5 degrees
Sand Dunning: 3 – 4.5 degrees
Desert Racing: 6.5 degrees
Recreational: 3.5 – 4.5 degrees
Toe
The toe-in or toe-out of an ATV refers to a measurement taken between the front tires. The first measurement is taken between the leading edge of the two front tires. The second measurement is taken between the trailing edge of the two front tires. The difference between these two measurements is the ‘toe’ of the vehicle. If the measurement taken between the leading edges of the front tires is less than the measurement taken between the trailing edges, the vehicle is said to be toed in. If the measurements are reversed, the vehicle is said to be toed out. An ATV should never be toed out. If an ATV is toed out, it may dart unexpectedly from side to side. This darting effect is magnified in sandy or deep loamy conditions.