Welcome Garry
Carbohydrates when digested will turn to glucose and cause your levels to rise.
So base your meals around any meat, fish, egg's cheese or other protein if you don't eat meat.
Above ground leafy veg and salads and healthy fats like olive oil, butter.
Avoid as much as possible bread (all types and colours) rice, pasta, spuds and most fruit
Have a look at the link below for the nutritional thingy, for some useful information, and here's a couple of other links you might find useful
https://lowcarbfreshwell.co.uk/
https://www.dietdoctor.com/low-carb