Teachers review the 21CLD rubrics that define each 21st century skill (e.g. 'problem solving');
Then they analyze and code an existing learning activity (lesson) according to one rubric (for example, does a science project on cell structure score a 2 or a 4 on the "problem solving" rubric?);
They review student work done as a response to the lesson and code it;
Then they refine the lesson to have a higher score on the problem solving rubric – providing students with more in-depth opportunities to develop this skill.
They follow this same process across many different rubrics, lessons and student work products.