The 5 cent lecture:
Its all about the tire friction circle. The tire can only give 100% of its traction before it starts slipping. If you are accelerating at the tire's limit, you can't steer. Same goes for braking. Similiarly, if 100% of the traction is going to steering, you can't use any brakes or gas.
This says bike, but its the same for a car:
For now, think of a standard apex corner, where the apex is in the center of the turn. (green line)
As you approach the corner, you will want to go hard into the brakes. Then as you start to turn, you want to ease out of the brakes. The more you turn the less you brake, until you aren't braking anymore, and devoting all your traction to turning. This should be near the apex. Then after you pass the apex, you want to start unwinding the steering and slowly apply the gas. The straighter the wheel, the more gas you can provide, until you are fully back on the gas.
Then there is late apexing and early apexing. You don't want to think of doing early apexing. (has special uses). Late apexing is safer, and usually taught to start out on.
If you really want to learn more, I suggest you sign up for a HPDE with NASA. They will teach you all this, and give you 3-4 hours of on-track experience learning all of this. It is much much safer than on the street. You never know what is going to happen on the street.