Viktor,
As you can see I am an SFO. I just joined this site yesterday and attempted to respond to you but for some reason I was told I was not properly logged in so the post was lost.
You generally become a member of the SFO by spending a period with the formation director of a local fraternity. This period used to be called a novitiate but is now also known as inquiry and formation. It allows you to find out about the order, discern if it is the right path for you, and have your initial instruction about the order, it’s requirements, and benefits. This period must take at least a year and I believe it may now require even longer.
The site mentioned above is that of the national fraternity in the US and has a listing of all regional and local fraternities there. If you are not in the US you should be able to get information through a local Franciscan monestery, convent, or church staffed by Franciscan clergy. If none are available locally I would try the office of your local diocese.
In the US the book “Catch Me a Rainbow Too” by Lester Bach, O.F.M. Cap. is used by many fraternities for intitial formation. It is published by Barbo-Carlson Enterprises, Lindsborg, KS phone 785-227-2364. (ISBN 0-944996-22-1). If you are not in the US your national fraternity may have similar materials.
I haven’t yet had a chance to search the site for posts by or info about other SFOs. Perhaps we can get a thread started for further discussion.
May God bless you in your journey.
LouiseL_SFO