A linking verb is also called a copula or copulative verb. It shows no action. Instead, it links the grammatical subject usually to an adjective, sometimes to a noun. All the verbs denoting the five senses are linking verbs: sound, look, taste, smell, and feel. These words typically link to adjectives. Other linking verbs include: appear, to be, remain, seem, become, stay, and others.
Here are some linking verbs linking the subject to an adjective:
He looks sick.
She sounds troubled.
They remained calm.
I feel bad about that.
Please note that the linking verb feel links to an adjective, not an adverb. Many otherwise smart people say I feel badly about that. No. Correct usage requires I feel bad about that.
Finally, you may use seem and some other linking verbs to link to noun:
She seems an honest woman.