Until you can get some more help / guidance from your dietician, here's a bit of help:
You will probably find it easier to work out portion sizes if you weigh what you want to eat - at least the parts which contain carbohydrate. We have a small digital scales with tare function (so you can place a plate / bowl etc on the scales, then add food, which cost around £10, and
Most food packets have carbohydrate content in the nutritional information - you need to count total carbohydrate, not just the sugar, and also bear in mind some foods have different values for raw & cooked eg pasta. Having said that, once I've weighed a food once, I just estimate by sight after that, which is useful when eating away from home. For fruit and vegetables, you'll need a guide, either book or online - others have recommended "Collins Gem Carb Counter: A Clear Guide to Carbohydrates in Everyday Foods", pocket size, £3.99. In practice, of veggies, you can assume that only potatoes and baked beans in tomato sauce contain carbohydrates.