diff --git a/contributing/sigs-and-committees/security/onboarding.md b/contributing/sigs-and-committees/security/onboarding.md
index 951e5ba..f48c601 100644
--- a/contributing/sigs-and-committees/security/onboarding.md
+++ b/contributing/sigs-and-committees/security/onboarding.md
@@ -1,3 +1,19 @@
 # Committee Security - Onboarding
 
-TBD
+If you are interested in joining COMSEC, please make sure to follow the steps listed below. For now all steps are manual, there's not yet automation or data-sync between different platforms in place. We hope to be able to change this in the future.
+
+Should any of the links below be broken or descriptions inaccurate we highly appreciate a PR with corrections.
+
+## Group memberships
+1) Request your membership to the [Discourse Group "Committee: Security"](https://forum.aux.computer/g/committee_security/)
+2) Request your membership to the [Github Team "Committee: Security"](https://github.com/orgs/auxolotl/teams/committee-security)
+3) Add/ update your membership status in the [community repo])(https://github.com/auxolotl/community)
+  - Add or update your user settings in [`users.nix`](https://github.com/auxolotl/community/blob/main/users.nix)
+  - Add your user to list `committees.security.members` in [`memberships.nix`](https://github.com/auxolotl/community/blob/main/memberships.nix)
+
+  Make sure to stick with the alphabetic ordering for readability!
+
+## Communication channels
+Make sure you have joined the following channels on Matrix in which ad-hoc communication takes place
+- [COM: Security - Governance](https://matrix.to/#/#COMSEC-GOV:auxolotl.org)
+- [COM: Security - General](https://matrix.to/#/#COMSEC-GEN:auxolotl.org)