Read the poetry aloud slowly, noting where your voice passes over syllables quickly and more quietly and emphasizes other syllables by saying them longer and more loudly. For example in "To be, or not to be, that is the question," you have several stressed syllables---"be," "not," "be," "that" and "ques." A syllable is a part of the word that contains one vowel sound, not the entire word, unless there's only one vowel sound in it.
Count the syllables and look for a pattern. In the quote above from "Hamlet," you'll find 11 syllables. The first six syllables follow one pattern. The second five follow another.
Write the pattern above the words on the paper. "To be, or not to be," has the iamb pattern. The second syllable is stressed, so you would write a / above "be," "not" and "be" and an x above "to," "or" and "to". The trochaic is the other pattern that has just two syllables and it is the opposite of the iambic. Thus, the first syllable is stressed and the second is not. In "that is the question," you can hear the dactylic meter. "That" and "ques" is stressed but "is," "the" and the last syllable are not. For dactylic, the first of three syllables is stressed; for anapestic, the third of the three is emphasized (And the SOUND of a VOICE that is STILL); and for spondee, all three are stressed (BREAK, BREAK, BREAK/ On thy COLD GRAY STONES).