Step 7: Validate
Structure text ought to be valid
For various reasons not explained here, your text should be valid, i.e. respect the rules for your type of structured document. If you are unhappy with these rules, write new ones or complain to your SGML guru.
(1) The validation feature
Menu: Element->Validate ....
Will you show invalid parts (step by step like a spelling checker). With the above operations you can fix things. Mostly you just need to insert missing elements or missing parent elements.
(2) Look at the structure window
This is an alternative method. Elements in wrong positions etc. are shown in red.