If flying as student with an instructor, instructor is PIC therefore his/her name is entered in the PIC column and the flight time would be entered in dual column (also in total time column).
Single Pilot / Multi Pilot has nothing to do with how many pilots are int the aircraft, but relates to whether the aircraft you are flying is certified for single pilot or multi pilot operations (i.e. requires more than one pilot to legally operate the aircraft). So for example Piper Cherokee - Single Pilot SE, Seneca - Single Pilot ME, Boeing 737 - Multi-Pilot.
Hope this helps.