Click on the "Find People" link and type in the name of the celebrity you want to follow. It will then display a list of possible matches. The one with a blue & white check mark means that the account has been verified to be the celebrity in question. You will notice that there are other twitter accounts that may discuss them as well.

Follow their accounts, you will get their updates in your feed and can respond to them.
Twitter is simple to use, you can follow others, make tweets, participate in discussions on different topics. Twitter is an amazing place for businesses to grow and generate leads.