Aheroic couplet consists of two rhyming lines of verse with four iambic feet two unrhymed lines of verse with five iambic feet two rhyming lines of verse with five iambic feet two rhyming lines of verse with five trochaic feet

A heroic couplet consists of two rhyming lines of verse with five iambic feet.
The word couplet refers to two lines - a couple means two. Iamb means that there are two syllables involved - the first syllable is unstressed, and the second one is stressed. Finally, heroic couplets are written in pentameters, which means they have 5 meters/feet, and each meter has 2 syllables, so there are 10 syllables in total in each line.
An example would be:
Then share thy pain, allow that sad relief;
Ah, more than share it, give me all thy grief

Two rhyming lines of verse with five iambic feet