I don't blame you for finding airplane flight to be a complicated subject. It takes many people and many hours with supercomputers to really understand the details of airplane flight. Here are the basics:

There are two keys to airplane flight: the shape of the wing and the engines. Let's think about what happens as an airplane gets ready to take off. First, the pilot turns the engines on high. This gets the airplane moving fast on the ground. Now, we know that the engines are parallel to the ground, so they do not directly cause the airplane to lift off of the ground. The important element for taking off is the wing shape. The wings are designed so that they are nearly flat on the bottom and curved on the top. As the engines start the plane moving, air must go either above or below the wings. The air that goes below the wings has a shorter path to travel than the air that goes above the wings. As a result of this difference, the air travels faster over the top of the wing. The air that travels faster over the top is more spread out than the slower moving air on the bottom, and as a result the air on the top is at a lower pressure than the air on the bottom. This means that the higher pressure air on the bottom pushes up on the wing more than the lower pressure air on the top pushes down on the wing. This creates a lift on the wing. If the plane is moving fast enough, there is enough lift to cause the plane to take off. Once the plane is in the air, this lift force keeps the plane in the air as long as the engines keep the plane moving.
I have something for you to think about. When a plane is stopped, the wings sag a little from the weight of the engines (and from their own weight). When the plane starts moving, the wings straighten out. From what I've told you, you should be able to figure out why this happens. Good Luck!