Removing items from templates

I am knew to blogging, I usually work with GoLive web design program. I am stepping in and taking over (free of charge) a site for nonprofit org. They do not want categories, calendars, search, and some others. How do I remove these from an established template? I am little worried about just going in and deleting code. I have done some but cannot seem to find where I can delete the category or the search. How much control do I have over an established template?