give a more precise reference

Author: 6mingkun

src/doc/en/installation/launching.rst

@@ -9,9 +9,9 @@ Notebook from the command line.
 
 If you did install the Windows version or the macOS application you
 should have icons available on your desktops or launching menus. Otherwise
-you are strongly advised to create shortcuts for Sage as indicated at the end
-of the "Linux" Section in :ref:`build-from-source-step-by-step`. Assuming
-that you have this shortcut, running
+you are strongly advised to create shortcuts for Sage as indicated in the part
+6 of the "Installation steps" Section in :ref:`build-from-source-step-by-step`.
+Assuming that you have this shortcut, running
 
 .. CODE-BLOCK:: bash