The first part on Orthographic on Joan Sedita's blog post may be found here.
How does orthographic mapping develop?
The following are extracts from the blog post found here and my comments.
Three intersecting skills must be in place to enable orthographic mapping (Ehri, 2014; Kilpatrick, 2015):
Highly proficient phonological and phonemic awareness
Automatic letter-sound correspondence knowledge
The ability to accurately and quickly decode a word by identifying its sounds letter by letter, and blending those sounds to read the word.