Once the mRNA is in the cytoplasm the smaller ribosomal subunit will connect to it. It will then slide in the 5' to 3' until it reaches the initialization codon ( AUG), once this happens the TRNA that carries the methionine aminoacid binds to the initialization codon. This is possible because the TRNA has a specific region caleed anticodon that recognizes the AUG cdon and binds with such by pairing.At this point the mrn is being contained bt both ribosomal subunitsand a second tRNA molecule connects too the following corresponding codon, a peptidic bond is then created between the aminoacids.As the ribosomes move ( 3 bases at a time) more tRNA molecules are being connected one at a time and being released once the peptidic bond is creted.When the ribosome reaches a finalization codon ( UAA , UAG or UGA) the proteic synthesis finishes, the last TRNA molecule leaves the ribosome which separates releasing the polypeptide, and so does the mRNA one which became available a new posterior translation.