Freshman admission into specific schools

<p>I am applying to the University of Wisconsin, and on my application, I listed that the major I was interested in as actuarial science, therefore I am attempting to apply for what the university describes as a General Course - BA degree (since you are admitted to the university as a freshman and the school of business as a sophomore). However, I also have interest in a computer science major, which is in a different school entirely (the college of letters and science). My question is if I do decide to pursue a major in computer science, what would the process be of doing so. Would I need to notify the university before I went there as a freshman (assuming I am admitted) that I have changed my major from what I listed as my intended major on my application? Furthermore, I am somewhat confused by the General Course description. This seems to indicate that I could take whatever classes I want as a freshman. And for a final question, are majors declared at any specific point the way they are in liberal arts colleges?
-Thank you very much for your time.</p>