Each codon is a triplet and codes for one amino acid. In the strand above separating it into triplets will reveal codon and amino acid number.
CAT CTA ACC CCA GAG GAG = 6 Amino Acids
mRNA is a translation of DNA into a convertible protein substituting T with U. Transcription is the first step and is already shown. The template strand is transcribed to:
GTA GAT TGG GGT CTC CTC
You'll notice it is the exact opposite of the template strand. The next step is to translate it into mRNA. Each of the following codons codes for a particular amino acid. I've included the actual amino acids they code for and included the link to the table.
GUA GAU UGG GGU CUC CUC
Val Asp Trp Gly Leu Leu
These amino acids can now combine to create a hemoglobin protein (with the addition of iron).