I have heard the grams of carbs can be anywhere from 50-100g on Phase 1 and that is with dairy, legumes and tomatoes, like Ruth said. We don't count anything on SBD though, that is the plus of SBD!
In my case, I do log my food in a calorie counter so that I can see what I am eating and although I do eat about 60g of carbs on Phase 1, I also eat about 30g of fiber so technically I eat about 30g of carbs a day after all the math is done. I don't try for any specific amount, I just eat according to plan and this is what it usually comes out to.
Good luck to you!