The RPM Spec Wizard is an interactive tool to create new spec files. It has a multi-step process, asking for necessary information like name, metadata, sources, patches, and requirements. At the end it spits out a spec file usable to build new RPM packages.
The Fedora project has its own documentation about packaging and best practices. These can be helpful to understand what the wizard is doing. https://docs.fedoraproject.org/en-US/packaging-guidelines/