As stated in the notes about the command format in your User Guide, Optional parameters are indicated in square brackets, and parameters that can be used multiple times come with a ... after. Thus, the command format for adding a plan should be addp d/DESCRIPTION [t/TAG]... instead of what is shown in your UG in the screenshot below.
As stated in the notes about the command format in your User Guide, Optional parameters are indicated in square brackets, and parameters that can be used multiple times come with a
...after. Thus, the command format for adding a plan should beaddp d/DESCRIPTION [t/TAG]...instead of what is shown in your UG in the screenshot below.