Welcome to the forum. It can be a bit overwhelming to get a diagnosis but how much you will need to do depends on where you are on the diabetes scale and if you have been prescribed any medication so information about your diagnosis would be helpful so people can make appropriate comments.
There is plenty you can eat and making the correct choices will see your blood glucose levels come down. As it is all carbohydrates which convert to glucose cutting out the very big hitters like cakes, biscuits, sugary drinks including fruit juice and reducing portions of the other high carb foods like potatoes, bread, rice, pasta, breakfast cereals, pastry and tropical fruits and basing meals on meat, fish, eggs, cheese, dairy, nuts, vegetables, salads, fruit such as berries still give options for tasty meals.
Things to be wary of are ready meals, pre-prepared sauces as these can be high carbs. Looking at packets, tins and jars will become second nature.
Have a look at this link for good explanation and some ideas for modifying your diet, it is a low carb approach which you may find suitable depending on what medication if any you are taking.
https://lowcarbfreshwell.co.uk/