If a person is a beneficiary of a Estate and has not been contact, do legal notices need to be posted to try and find the person? If so, what does one go about find the legal notices?

Not certain I understand your question, but if I thought I were a beneficiary, I would contact the court in which the estate is being administered, and obtain more information. Beneficiaries are entitled to notice as a general principle.

Yes, the court has to make certain attempts to find the person. But then someone will have to file the will with the court for them to even be aware.