Did you complete some of the learning paths? If not, I would highly recommend this.
To your question:
- The ReferenceSelector is used to maintain the association. The type of association you need to use depends on your usecase. The ReferenceSelector is used to set the association from one object to the other.
- The steps you need to take in your microflow depend on what this microflow should do? Is it a datasource microflow? If so, you need to retrieve the obejct you want to show. Be carefull with database retrieves, if you did not commit your changes, it will return the false object or no object at all. In this case, use retrieve via association.
- The selectable objects microflow need to return the list of objects that should be selectable in your reference selector. Retrieve them (, filter them) and return them.