The war was so vast with so many different things going on that finding out what role your Dad played can be a difficult but not impossible task. The first thing is obtaining copies of his military records, which is not that difficult to do on line. The of course there is Mr. Google and Amazon Books for openers. Many out of date books are available that provide details that Mr. Google and Mr. Wikipedia don't have. However both couples provide clues as to where to search. The army records will provide the clues as to which web site to go to.
It took a while for me to trace my uncle's war experience despite the fact that he was in the 82nd airborne which was one of the most publicized divisions. I didn't have the benefit of his army records, but did have a news clipping from the old Brooklyn Eagle that my aunt had saved which gave me the clues to what campaigns he participated in. I learned that his regiment engaged the SS division Vendetta at the Mussolini Canal, and that he was one of the few survivors who went to Normandy after Anzio. I knew he was wounded in Holland in Oct 44, and determined it was on the Siegfried line based upon the histories given on line.
An old out of date book on Anzio provided a lot of data not contained on line. Remember the author who wrote these older books relied on information no longer readily available.
A lot of it is guesswork and note taking, ruling stuff in, and ruling stuff out. If your Dad was in the Battle of the Bulge, chances are he was in Normandy, and most of the battles through France. You can figure out some of his movements by his Division numbers, whether he was under Montgomery when they split the armies up after the Budge attack or with Bradley.
Remember 200,000 a week for five full years were killed during World War 2. It's a big story and there is a lot of material out there. Finding personal information can be like looking for a needle in a hay stack. However there are individual web sites set up by vets, that publish old photographs and memories. So the search can be worth while. I did get a rush looking at my Dad's military records, and seeing his signature on his pay documents.
I would be happy to provide you with any answers I have as I have more then two thousand books on the subject.