The phonic dominoes are played in the same way as conventional dominoes. Instead of matching dots, these dominoes involve matching sounds (rhymes/rimes with different onsets). So, "rat" can be matched with "hat", "mat" or "pat", for example. 
Set 1: CVC (consonant-vowel-consonant), -ll and some initial blends
Set 2: CVC, sh, ch.
Set 3: final blends, -ou-, -oa-, -ai-, -ea-, -ng