The 13th-16th Rays focus on higher manifestation - to become and work for the universal and divine plan. They are the first level above the planetary levels of earth. They also focus on connecting with, and integrating with the monad, the monadic level.
This level is available for working with 1:1 sessions with each Ray separately, and I recommend working with the previous 12 Rays for some time before entering this level of vibrational work, and then to do at least 2-3 sessions / Ray before moving on to the next level of vibration.
During the 1:1 sessions we look at the qualitites and step of each Ray, and we go through questions and other information or support needed in the process.