Hi Tex Gore and welcome.
The usual food testing regime is to test just before you eat, and then two hour later. I'll explain.
The first test establishes a baseline. Then you eat.
Assuming there are carbs in what you eat, within 20 minutes or so those carbs will start to be digested and pass into your blood. This happens at varying rates. it can be affected by how efficient your digestion is, what else you've eaten along with the carbs, the type of carb, whether the food is hot or cold, for example. Not all things affect all people all the time. GI has no impact whatsoever for me, for example, but hot milk hits me really quickly for even a very small amount.
As the glucose hits your blood stream, this also triggers the production of insulin. It will immediately start to shift the blood stream glucose into muscle and central nervous system cells. So for a period glucose will be being added and taken away at the same time. This usually means that peak blood glucose level is reached somewhere in the first hour.
What you're actually testing for at +2 hrs is how efficient your body is at clearing the glucose - you are not testing to see "how high you go". What you want to see (ideally) is that your levels have returned to where you started, or at least very close to that - within two points. You also should be under the "normal" BG figure, which is usually said to be 7.8 for non-diabetics or 8.5 for T2s. I just go for under 7.8 myself.
So starting at 5.3, +2 hrs 6.5 - fine
Starting 5.3, +2 hrs 7.8 - more than two points above start, too many carbs to be dealt with properly
Starting 5.3, +2 hrs 9.5 - more than two points above start and out of normal range.
If your levels aren't where they should be on the second test, that means there were too many carbs in what you ate for your system to deal with properly. The excess glucose will both hang around in the blood (high blood glucose over time can cause damage) and be stored as bodyfat.
You can do all this with fingerprick tests. Libres and other CGMs show you what happens when you're not testing, which can be very informative once you've worked out what's going on.
Does that help? Ask questions please, it's a lot to take in.