Hi De and welcome to this forum. I'm sure it's overwhelming when you're first told this. For some information about
general facts and diet, please read the two pinned stickies at the top of the Diabetes forum and also this website:
http://www.bloodsugar101.com/ which is very in depth and has a lot more specific information.
Generally, doctors want you to test the first thing in the morning before you eat or drink anything to see what your fasting blood sugar is. They want it to be under 100. (For diagnostic purposed, they say that fasting between 100 and 125 is pre-diabetes and 126 and over is diabetes - but this would be consistently not just once or twice.)
Then, testing about two hours after you begin a meal will show how you metabolize the food you're eating.
Diabetics do not metabolize carbohydrates normally as non-diabetics do and this is why we are advised to stay away from sugar and any food made with sugar as well as flour-based products like bread, pasta, etc. and rice and potatoes. These are carb-laden food that will raise your blood sugar. Low-glycemic food (you can find lists of these on the web everywhere) are best. Proteins like meats, fish and poultry are fine. Vegetables other than potatoes should be ok but be careful of gravies and sauces because they are made with flour.
The best way for you to know what food affects you is to keep a daily log of: date, time, blood sugar, food, etc. A little notebook is good or just papers clipped together. Depending on how many test strips you can use per month (if your insurance limits you), you might test several times in one day and then skip a day. If you test before you eat, then eat and then test 2 hours after you started eating, you'll see how many points your blood sugar rises in reaction to the food you eat.
I know this might be a lot to absorb at one time. If you have any questions at all, please just ask! 