In Basics you set:
the Topic's name and description;
its reference prefix (items are numbered
PREFIX-0001,PREFIX-0002and so on);its colour and icon, so it's easy to spot in lists;
how items move: a workflow template to start from, from very simple (Open → Closed) to more detailed. You can change the workflow afterwards in Workflow;
when an item has several restricted values: Broad (the usual choice: an incident at two sites shows to both site managers) or Narrow. See Topics, items, roles and access.
For a new Topic you can pick the workflow template before choosing Create the Topic; it's applied straight away.