You pick a ten year span. You pick 1, 2 or 3 years in that span to twist from, and players must be twisted to versions from the remaining years.
So if you took the 2006-15 Dodgers, and twisted '06 and '12, that means EVERYONE on your roster must be twisted from those two years, and the versions you roster must be from 2007, 2008, 2009, 2010, 2011, 2013, 2014 or 2015. No one on your final roster can come from 2006 or 2012, though they must have played on one of those teams in real life.