What documents do I need to begin a real estate purchase or sale?

A signed agreement by all Sellers and Buyers stating all the terms and conditions of the parties.

What needs to be done to "settle" an Estate?

If early enough in life, one should know how to provide for long term health care. Everyone should have appropriate documents to be taken care of such as Durable Power of Attorney(s); Living Will; a Will and/or Trust if appropriate.