How are aeronautical procedures created in the US?
does a worker go to an airport and monitors all information, and choose what kind of approach/departure (for example) will be? Or do airport workers advise regulators (charts creators)?


Yes. :)

Airport/airspace procedures are mainly created by a country's local aviation authority, so if you want an instrument approach to your private airstrip in the US you would contact AFS-420, the FAA's procedures branch, probably through someone at your local FSDO, and ask them to work with you to develop the procedure.
The Procedures people will survey the approach and design a procedure that makes sure you won't hit anything on the ground, and ensure that your procedure won't conflict with other existing procedures.

Once the procedure is designed they'll test-fly it - that's done by another group - and if everything checks out they'll publish charts for it.

Once published the FAA will periodically re-evaluate then procedure, both through flight checks and other feedback (if your new procedure is generating a lot of noise complaints for example the FAA will work with you to reduce the impact).