Proteins destined to be secreted from the eukaryotic cell are synthesized by ribosomes bound to the RER (rough endoplasmic reticulum). As the protein is synthesized it is translocated withthe rough endoplasmic reticulum membrane into the lumen of the rough endoplasmic reticulum where it folds into its last conformation.  The ER then buds off vesicles which handle the protein to the Golgi apparatus also called as the Golgi complex that is shown in the figure. The Golgi has a cis face (where vesicles enter) and a Tran's face (where vesicles leave). Thus the RER vesicles fuse with the cis compartment of the Golgi and releasing the protein into the Golgi lumen.  The protein then moves by the Golgi complex to the Trans compartment being changes en route through the addition of carbohydrate residues (glycosylation,).

Figure:  Synthesis and exocytosis of secretory proteins; see text for details. The ribosomes attached to the RER are represents as filled-in circles while the open circles in the lumen of the RER, vesicles and Golgi complex show secretory protein molecules.