What is Lincoln 10% plan?

3 answers

http://www.sparknotes.com/history/american/reconstruction/section1.rhtml
Can you explain what it means please
What part of this don't you understand?

"Lincoln’s blueprint for Reconstruction included the Ten-Percent Plan, which specified that a southern state could be readmitted into the Union once 10 percent of its voters (from the voter rolls for the election of 1860) swore an oath of allegiance to the Union."