In the past, formal GeoMIP experiments have been discussed by all GeoMIP participants. This opportunity for comment and discussion is central to the values of GeoMIP. In recent years, GeoMIP has also included the Testbed, which is an opportunity for members of the GeoMIP community to propose new experiments. Testbed experiments are not considered formal GeoMIP experiments, and up to this point, there has been no formal procedure for adoption of a Testbed experiment as a formal GeoMIP experiment. Here we outline these steps.