Hello. That's very scary. I would very much have hoped that you'd have more than that. And even if you did, as you are pretty much in shock being presented with a diagnosis and its unlikely youd have taken enough in to be useful. As everyone is so different, we won't be able to advise you on how much or when to use it. But insulin users may be able to tell you a little.
If you were on a ward in the hospital, I'd ring them directly and ask them to give you more advice. If not, they should have given you information about the diabetic team, etc. Contact them as a matter of urgency.
If all else fails, ring 111 and explain the problem. They may be able to direct you to the right place and at least to an on call gp who can give at least some advice or they in turn can direct you.
The good news is that you will be able to manage diabetes in the long run and this is a great forum for support and advice.