In the simplest cases, the two fractions will already have a common denominator. In this case, add the numerators and then reduce the resulting fraction.
There are thousands of algebra books out there that break down algebra to its easiest components. Many learning styles in these books are different so take the time to go through them and find one that looks like you might understand or one that accommodates your learning style. Many books explain some algebra concepts better than other. Choose a variety of books or online courses. You can get a live tutor. It will be much easier to learn from someone who s already familiar with the concepts of algebra. There are online communities where people discuss their algebra problems and help each other. Remember though that even if you are a member of one the many popular interactive algebra communities you still need to study and practice a lot.