You can proceed in two ways:
(recommended). The system offers standard situations for selection and executes the corresponding generation steps. You need no detailed system knowledge and can be sure that all required steps are performed.
You must understand the generation process completely. It is designed for situations that are not covered by the standard. You must choose the generation steps yourself. There is a risk of unintentionally deleting maintenance modules or performing the generation only incompletely. It is therefore not recommended.
Proceed as follows:

If you want to use the expert mode, choose Expert instead of selecting options. In the subsequent window, enter the components you want to regenerate.
See also:
Make Dictionary changes