If you're storing your milled flour, make sure it is cool to the touch before sealing it in any container.
Unless you're using the milled flour within the week, refrigerate or freeze it. All whole grains and legumes contain oil in the germ which can become rancid over several months if stored at room temperature. Soy beans are especially high in oil (I notice your grain mill can make flour from legumes - very nice!). All whole grain and/or legume flour keeps well if frozen.
Burying a few fragrant bay leaves in your whole grain is supposed to discourage insect infestation.
Keep your whole grains clearly labeled, including date of purchase. For example, it is difficult for the beginner to distinguish soft wheat grain from hard wheat grain but they make different flours. (Soft wheat, when milled, makes whole grain *pastry* flour whereas hard wheat makes whole grain "bread* flour.) Also, clearly label the resulting flour (type and date of milling) if you're going to store it.
Besides milling flour, try experimenting with cracking grain. For example, speciality grains like kamut and spelt crack cleanly and the cracked grain can be cooked like bulgur. (You could also try cracking any hard wheat). I like to use these cracked grains to make tabouli or as a substitute for rice.
I'm sure you'll enjoy your grain mill. It looks very versatile.