What do you mean by inside curve and an outside curve? Assuming a right handed pitcher, a screwball is a pitch that curves toward a right handed batter. A curveball is a pitch that curves away from a right handed batter.
Are you asking how to throw a curveball and a screwball? Or are you asking how to throw a curve that ends up at different locations at the plate?
I set up 3 ft parking cones to the left and right of the plate and then set up to catch behind the plate and cones, my kid works in and out. We never pitch over the center of the plate. Where the ball moves is based on the rotation of the ball. Generally curve ball is thrown fingers up like a crown across the front of the body finishing the release at the opposite hip. Screw ball is fingers down spinning the ball inside out. The key is rotation of the ball. Use the 4 seams to create movement