They write we must use adjectives rather than adverbs after linking verbs. For example https://www.macmillandictionary.com/dictionary/british/taste_2:
Food can taste sweet like sugar.
But here's an adverb https://www.macmillandictionary.com/dictionary/british/smell_2:
The laboratory smelled strongly of chemicals.
"to smell" as "to have a particular smell" can be only a linking verb. Therefore we must say:
The laboratory smelled strong of/like chemicals.
I'm confused in what cases we must use adjectives after linking verbs and in what cases adverbs. Help me please.