The default settings for object color are found in Project Settings (Edit > Project Settings, or command – D). Once you change it there, save your project (File > Save Project As…) as “new.c4d” (without quotes) to the Maxon R23 folder in Applications. Start from a blank scene (no objects, etc.) because whatever you have added to the object manager will also be created by default with each new project (which can be handy if you want certain objects, lighting set-ups, etc. to be created every time you start a project, but that’s probably not what you want for now).
For changing default settings for tools and objects I’ve linked a tutorial below, but this doesn’t work for project settings. And as far as a manual is concerned, use the built-in Help menu in the main C4D menu list, or by right clicking on any parameter and selecting “Show Help.”
https://www.youtube.com/watch?v=pAq_Cxip-2A
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