‘Tile 8 x 16 Type 2 with Space Shuttle Discovery Information Sticker’ for set 10283

[Sylvain Sauvage]

3. 'Affirm the CA' I couldn't find, that is why I couldn't find submit my part. (What means CA?)

CA = Contributor Agreement.
You need to say you are okay for your parts to be released under the Creative Commons Attribution Licence 4.0 International (CC BY 4.0).

Unfortunately, I can’t help more as I’m not sure how you agree now (used to be by email… or maybe I did it again when Orion upgraded the tracker?  I can’t remember 😅).
Isn’t there a checkbox?

Oh, there’s a dropdown in the user settings: https://library.ldraw.org/dashboard/settings but there’s only one option….