Hello everyone. I did a few searches and was not able to find the info I was looking for. I am getting back into the hobby now and am wanting learn what the different setting on my transmitter do and how to best use/change them. Is there a resource someone could point me to? Thanks in advance.

The instruction manual should cover all that. A quick summary would be:

Basic (almost every radio should have these):

Trim - used to make the car drive straight
EPA (end point adjustment, left and right independently) - Set these to limit how far the servo steers so you don't wear out the servo by pushing it against the steering limiters on the chassis
Dual rate - Turns down the overall steering amount, similar to EPA but affects left and right simultaneously. Set this to 100% when setting EPA. Then adjust dual rate to reduce the amount of steering if needed. Helpful on flowing tracks if your car is oversteering.

Advanced (check your manual if you have these):

Exponential and other steering/throttle curve adjustments - useful for reducing twitchy steering around neutral without reducing steering at full lock for the tight corners, or softening the throttle to reduce wheelspin
ABS (anti lock braking) - If you're too heavy on the brakes, the tyres can lock up and make the car behave unpredictably (usually understeer in FWD or 4WD, oversteer in RWD). This can be used to reduce this.
Sub trim - similar to normal trim, but this is usually done during initial setup for large trim adjustments. Set trim to 0, use sub trim to get to the right ballpark, then fine tune with normal trim. Usually trim doesn't affect EPA settings and sub trim does.

Thank you very much for the help.

Be aware that things are not always called the same from radio to radio. For example, the on-the-fly brake epa (the one by your thumb) on a Futaba radio is called ATL. That's were the manual really does come into play.

Epa can also be used to slow down you RC. Throttle epa that is. I have a 6yr old and a 3 yr old. They like to drive my truck but I wouldn't dare just let them have at it with the 6.5t I have in there. So I'll drop the throttle and brake epa to around 45-50. Gives them a nice smooth throttle response while also making sure they aren't driving it like a rocket. This may not apply to you but thought I would share anyway.