The ground is frozen, what should I do about a soil sample?
When completing the course in the winter, before the ground freezes solid, collect a 1 cup soil sample from an area you'd like to have the soil tested for. You can keep it in a plastic bag in the freezer until needed for the course. This article describes how to take a soil sample: https://www.finegardening.com/article/how-is-your-soil-texture
The soil can crust over with frost/ice but just below the surface, with a good spade or pick the soil is usually dig-able; also, closer to buildings the soil freezes last.