Complex sentence: On January 1,2014, Kyary herself confirmed the new single which in untitled in her new year's message and later confirmed the title later in her birthday concert on January 18--19,2014.
Split into simpler sentences: On January 1,2014, Kyary herself confirmed the new single, then untitled, in her new year's message. She announced the title later in her birthday concert on January 18--19,2014.