You can set default 2:3 pulldown sequence reference frames for all tapes and record clips. In cases where you frequently receive tapes that require 2:3 removal, it is a good idea to communicate with your client so 2:3 sequence is inserted consistently for all tapes. That way, your default settings configure an accurate 2:3 removal process without you having to manually enter reference frames tape-to-tape.
You can also set preferences to highlight and correct hybrid frames, and to apply a timewarp fit to native 30 fps interlaced material referenced by EDLs for which 2:3 removal is disabled. That way, native 30 fps material can be integrated in 24 fps timelines more easily. See 2:3 Pulldown Options Menu.
To set the default source 2:3 pulldown (for material on tapes provided to you), select a frame type. You do not have to enter a reference timecode.
You can override these default settings on a tape-to-tape basis. See Overriding Default 2:3 Pulldown Configuration Tape-to-Tape.