To join the CERS is very easy.
Any group or historical association can ask to become a member of the C.E.R.S. provided that when formally submitting the application, this is accompanied by a letter of presentation of a group already belonging to C.E.R.S. and relative documentation demonstrating the quality and seriousness of their work.
Ask the Application to email@example.com or go to take it to the "Download page" of this side.