What I Want To Learn About Computers

Computers are very exciting machines, and they sometimes give me lots of fun stuff to me, sometimes help me a lot. However, it is more exciting and helpful for me to know about composition and excel.
To tell the truth, I cannot play any music instruments, but I want to try to create music by myself. If I know how to operate the software of composition, it will be the great and most exciting friend for me as I can do many things. I can create music by piano sound, guitar, and also I can compose music electronic sound. I can use any music instruments and combine those sounds for one music. Thus, I want to learn about a composition software.
Also, I want to learn about excel. Although, I actually have learned about it in my high school, and I have used it when I did accounting class's assignment, I did not use it efficiently. Because excel will be a good software for me in the economic field.
Therefore, I want to learn about how to compose on the computer and to use excel.