When a Pool is registered on Mainnet will it automatically appear in https://adapools.org/ or does the stake pool operator need to create an account and enter all the information (or some needs to be entered manually while some is automatically populated based on Pool ID)?
Much appreciate any guidance.
Yes, it shoul appear automatically, if not check the metadata hash
Noted Alex, but what about for example the Welcome Message, that I see associated to a Pool how is that added?
When you create an account with Adapools and claim the pool (prove you are the owner by clicking on claim link on pool page), you will be able to add other data through their management interface.
Also there you can add other data lice icon, socials etc through the extended field in the medatafile which adapools will process.
See explanation here: