I recommend the YouTube channel: The Great War. For the last four years they’ve done a weekly installment of what happened in WWI exactly 100 years ago. Obviously next week’s edition will finish the series. I started view about 2 months ago and am now in the middle of 1915. I thought I knew a lot about WWI (I taught history) but I learn something new in each 10 minute episode. They also have specials on the run up to the war. They cover just about every aspect of the war—the Eastern Front, the Middle East, Africa and the Pacific—not just the Western Front.
One interesting thing I learned is the one man in the Austro-Hungarian leadership who was dead-set against any war was Archduke Ferdinand.
His license plate on his car-A111 118.