do I have to have an appointment to research my genealogy

To do self guided research or to get general help from the missionaries there no appointment is needed. If you are in need or a specialist in a foreign country or someone who speaks a specific language it is sometimes a good idea to call or check in on the appropriate floor to find out when someone might be available.

You can just come in to do research. Of you need a specialist to help, check at the desk of the floor concerning the country you're interested in to see when someone is available.