This is the sequence used in the Spelfabet materials, which like all synthetic phonics teaching sequences works from short, simple words to longer, more complex ones. It’s not the best or only possible sequence so please adapt it as necessary to meet your learners’ needs.
Level 1: words with 2 or 3 sounds and “short” vowels (VC and CVC)
Level 2: words with 4-7 sounds, “short” vowels and consonant blends (CVCC, CCVC – CCCVCCC)
Level 4: The many spellings of “long vowel” sounds (ay, ee, I, oh, oo, you)
Level 5: The many spellings of other vowel sounds (ar, er, or, ou, oy, air, ear)