This article from Microsoft reviews basic techniques for extracting part of a string, such as a first name from a full name.
It doesn't demonstrate newer techniques using the Split() function, but uses tried and tested approaches that should have broad application.
This article lists sample expressions that you can use to extract a portion of a text string. These expressions are commonly used in the Update To line of an update query to place a portion of a larger field into a new field. You can adapt these expressions so that you can use them with other common formats. For example, you can use the expression that is used to extract "Doe" from "Doe, John" to extract "Seattle" from "Seattle, WA."