Hi Goonergal and welcome to this exclusive and very friendly and supportive club.
To start with you really need to test before and a couple of hours after each meal and this will start to give you an idea about how different foods affect your blood glucose levels. You'll then be able to see which foods to avoid and just as importantly what foods don't spike your BG. If you keep a record of your results, and even better still a graph you be able to see how your BG is improving as the weeks and months go by.
When I started testing 12 months ago, to start with I tested more or less every day before and after each meal, but as time went by my results showed me what foods to avoid so I now test only every second day and for only for one meal on that day. The only exception to this testing pattern is that the evening before I'm due a pre-breakfast test I usual test just before bed and this gives me an indication of how my BG has changed overnight.