Having come from an Asian background, I have to admit that most of my previous "dining out" experiences have been either asian restaurants or the type that you'd find in any North American chain-type restaurant.
Now that I've started branching out, I've always wanted to order a charcuterie plate but haven't simply because of the fear that I would not know what to do with it when it came!
Do you put the meat on the bread provided and eat it like an open-faced sandwich?
Are you allowed to pick it up with your fingers?
Do you put it on your plate and then use a knife and fork?
I'm totally lost and I've already tried googling the answer with no results...
I would say it depends upon the place. If it's serious French, knife and fork would not be frowned up, but in a more casual place you might be expected to use your hands. Just making it into a sandwich seems odd to me for some reason, but it is your food so enjoy. (If you look around before you order you might see someone eating it....you could follow their lead.)
Once it's on your plate.....if it's soft, use utensils. If it's hard and can't be speared, use your hands.
I don't usually use my fingers, except for the bread. Sliced meats usually don't require any further cutting, but if necessary I'll cut the slice in half before eating it with a fork. I eat chunky paté with a fork and knife. I break off pieces of bread and eat them, maybe spread with or dipped in mustard. Stuff like smooth paté and rillettes, I spread on a piece of bread with my knife or fork. If there are gherkins, pickled onions, salad, etc., I eat them with a fork.
It's a little bit like eating a cheese plate. There's really nothing to fear! Unless it all somehow ends up on the floor or in your hair, you're probably doing more or less the right thing.
I was taught never to butter a whole slice of bread but rather put some butter on your bread plate and then break off a piece of the bread, butter it and put it in your mouth. I feel that is also the best way to deal with pate. At Xmas, I sat next to two guys in their 20s and they buttered whole pieces of bread and cut up all their food before they ate it--another thing I was taught not to do--so it may well all be generational.
At the risk of being OT, clearly your parents had some idea of table etiquette. The behaviours you described are evidence of why a business teaching table manners to grown men can exist.
But to the OP: I don't see why or how you would approach this with any more trepidation than you would an antipasti plate at an Italian spot. My daughter plays soccer with a bunch of Italian girls, and at our frequent dinners (either picnics or restaurants), I watch the other parents. They think nothing of taking a piece of salami, wrapping it around a piece of pepper or pickled vegetable, and popping it into their mouths. Utensils are sometimes used with larger pieces, but not always. I have never seen anyone construct a sandwich, though. As esco123 points out, they will break off a piece of bread, and eat that separately, between bites of other things. My advice: so long as you're not chewing with your mouth open and/or cramming so much in your mouth at one time that your cheeks bulge, no one else is probably going to care.