The CTAD Clinic on YouTube has excellent info on structural dissociation.
Dissociation made simple by Jamie Marich might be helpful. Not only about DID specifically, but covers a lot of dissociative work.
A place to talk about CPTSD.
No diagnosis checking is allowed, If someone says they have it, they have it. It's not your job to dig through someone's medical history. It's invalidating.
None of the very basic isms and phobias. Includes but not limited to racism, sexism, classism, homophobia, transphobia.
CW your post if it contains triggering topics. If you have to ask, just use a CW.