When solving integrals, you are basically doing the backwards of taking the derivative. It is like multiplying and dividing. Essentially, all you do is look at the function in the integral and you take a step backward to get the original. You can think of the function within the integral is the derivative and what you are looking for is the original equation. There is some algebra mixed in, but that stuff if easy. If you need help doing specific integrals let me know!