Do you have a kitchen scale? A gram is a unit of weight rather than volume, so you'd want to weigh out the ingredients. I have a really inexpensive kitchen scale that will give measurements in ounces and grams.
And yes, 200 degrees Celsius is 392 Fahrenheit.
Also, if you don't have a scale, there are lots of rye bread recipes online that are in U. S. measurements. Good luck!