Setup Type Sequence (also called Customize Sequence) is used to group a number of Wizard Beans together for the purpose of allowing the end user to select these beans when they select this Type of install from the Setup Type Panel. Typically, the types are "Typical" and "Custom". Additional setup types can also be created - See the MultiPlatform User's Guide, Chapter 3, Subchapter 3.5 - Wizard Panels/Setup Type/Creating a New Setup Type for instructions.
The Selected Setup Type ID property needs to be a value that was established in the Setup Type Panel for that type of install so that all of the Wizard Beans grouped together under the Setup Type Sequence are visited at runtime. If all of the Conditions of the Setup Type Sequence do not evaluate to true during runtime, then all of the Wizard Beans grouped together under the Setup Type Sequence are not visited during runtime.