Proteins that are destined for the plasma membrane or export to the extracellular environment in eukaryotic cells are translated on ribosomes that sit on the rough endoplasmic reticulum (RER).
The ER provides an oxidizing environment (for formation of disulfide bonds) and the necessary chaperones (folding assisting agents that are not part of the final protein).
A classic example are the disulfide-linked heavy and light chain polypeptides of antibodies secreted by B-cells of the immune system.
Other types of glycosylations include S-linked (via cysteine residues), C-linked (via tryptophan) and O-linked (via serine or threonine).
Once the vesicles pinch off from the ER they are transported passively (by diffusion) or actively (by intracellular motors that run on cytoskeletal tracks).
Tethers come in two "flavors": long protein(s) with domains called "coiled-coil," or complexes of many subunits which are for the most part globular.
This close juxtapositioning of the two membranes allows the interaction between SNARE's (soluble NSF (N-ethylmaleimide sensitive Factor) attachment protein receptor) on both compartments.
Incidentally, all 5 essential small subunits (Trs31, Trs20, Bet3, Bet5 and Trs23) are required to reconstitute efficient exchange activity on ypt1 in vitro.