When editing DDL sources, you will generally need to make use of the ABAP CDS language reference. Here, you can find more information about the syntax and meaning of ABAP CDS language elements. For this, ABAP Development Tools provides a context-sensitive link (F1 help) from within the DDL source editor. The CDS help content is displayed in a separate help view.
In addition, you may need to display the definition and documentation of elements used, like tables, views, or individual table fields that you used when defining CDS views in the DDL editor. For this purpose, press F2 to access the code element info popup.
To access the CDS language reference, position the cursor on a CDS language element or annotation for which you need help and press F1.
In the DDL source editor, move the cursor to the element of your interest and choose F2.