You have to think of gravity as a fabric, more like nylon. If you stretch the fabric across a large opening, like a bucket, and place a marble, you will see that the marble bends the fabric. If you put another marble near the first, you will notice that the marbles fall toward each other; or as they say, attract. Now, this is a 2 dimensional view of the fabric that makes up our universe. In 3-D, masses can fall toward each other from any direction, up, down, left, right, foward, behind...etc. Think of our sun as a giant marble in that nylon fabric. The sun would be in the middle. Now think of a planet like say, the earth with a radius of 1 from the sun. If you push the earth (marble) around the sun (marble), you will notice that the earth will swing around the sun and then fall toward the sun. This is a similar, yet very small scale model of our solar system and how the gravity works.