You do not have to fill in all the fields. e.g. If you want to search for your classmates in Ghana, just select Ghana in the “Present Location” field, and keep the other fields blank.
If you are not sure about a friend’s full name, you may try entering in only the first or last name. e.g. to find ‘Sarah Appiah‘, you may enter ‘Sarah’ in the first name field. The more fields you enter, the more accurate your search will be.