In August, when Thyme has finished flowering it needs to be trimmed back. This curtails its natural tendency to get leggy and keeps it in a neat shape. Don't throw away the prunings, they can be saved and used as dried herbs over winter.
You can dry them out in the oven on a very low heat, keeping a careful eye as they can go from nearly crisp to blacken very quickly. I think it is easier just to hang them in bunches in a warm place until completely dry. Then, using an ordinary screw top jam jar, clean the leaves from the branches into the jars ready to use.
In the first image Thyme is drying and in the second, Oregano. Both are herbs which respond well to this simple method of drying and will preserve well over winter. It’s nice when summer has long past to undo the lid of the jam jar and smell the dried herbs which you picked yourself. There are absolutely 100% as good as shop bought, free and no air miles. The supermarket Oregano I currently have in my cupboard states it is “the produce of more than one country” so it’s been around the world a bit. I hope I have picked enough to ensure future Oregano is the produce only of the garden.