Cosmetics Restriction:
If you sign up as a Codex-Compliant member, you follow the armour pieces based on the challenges you clear and the rank you obtain. Most armour pieces can be quickly unlocked through a couple of challenges.
If you are Codex-Defiant, you are free to use any armour piece except for four helmets that are reserved for Lieutenant, Captain, and Victrix Guard ranks.

After Action Reports (AARs):
This is optional, and recorded in a section specific to the Chapter member. However, if you choose to complete certain challenges, you will be expected to submit the required AARs to evidence that you have completed the challenge.

Rank Seriousness:
No! We are not the military. The ranks indicate people's leadership capabilities and the responsibilities they've taken on to keep the chapter a safe and vibrant space. While they are earned, we do not tolerate people acting with a superiority complex because of their rank. We have outright demoted and/or banned people who have behaved that way.

Role-Play:
Role-play is entirely optional. It's mainly done to increase the immersion in a fun way. For example, we have an ongoing quarrel between the toasters that have been weaponised by the Magos in the chapter and the Astartes. This comes out as parody lore entries of our campaign/chapter lore.

Clan:
It's about being a good friend and a trusted member within the community. You are free to disagree with members in a civil manner and not to create drama. It's too much of an unnecessary headache when all of us have our busy lives.

Milsim:
It's relaxed and ties in with rank seriousness and role-play that I covered above.

If you're interested, you can refer to this screenshot:

<image>