Glad to be here pre diabetic and not medicated trying lifestyle changes
Welcome to the forum.
A prediabetes diagnosis is a wake up message and a heads up that some life style changes are needed to prevent your blood glucose from crossing that threshold into a diabetes diagnosis however depending on how close you are to that will determine how much work you need to do.
Some modest changes may be all that is needed so being mindful of which are high carbohydrate foods and cutting down on your portion size. An immediate thing would be to cut out cakes, biscuits, sugary drinks including fruit juice as these are foods which will push up blood glucose being both high sugar and flour.
Basing your meals on meat, fish, eggs, cheese, vegetables, salads and fruit like berries with small portions of higher carb foods like potatoes, rice, pasta, bread, breakfast cereals and tropical fruits.
Have a look at this link for some ideas for modifying your diet.
https://lowcarbfreshwell.com/
Remember low carb is NOT no carbs but is suggested as being no more than 130g per day total carbs not just sugar. Protein and healthy fats do not convert to glucose and making sure you have enough to replace the carbs you are reducing otherwise you may feel hungry to start with.