Complex sentence: Perlman spent two years writing a draft, immersing herself in the "Guardians" universe, and was asked in late 2011 to create another draft, before Gunn was brought in in early 2012 to contribute to the script.
Split into simpler sentences: Perlman spent two years writing a draft, immersing herself in the "Guardians" universe. In late 2011, Perlman was asked to create another draft, and in early 2012, James Gunn was brought in to contribute to the script.