Gorgeous

Must I have to use "gorgeous" only for to describing how does someone looks like, or can I use it to describe any actions, the results of any actions, and so on?... can I

To answer your question, using "gorgeous" to describe an action is figurative speech.  The basic grammar and definition won't help you here - it really requires a taste for the language to use it properly, otherwise you'll sound very strange.

For the grammar in the question, pay attention to your modal verbs (may/must/etc) and gerunds/invinitives (for must be followed by a gerund here).

Be careful of switching to "question order" because you see a question-word.  If the question-word doesn't start the sentence, then you must use the regular word-order for a statement.  This is a very, very common mistake.