You keep a woolen garment beautiful by not washing it too often, airing it on a hanger is often sufficient. If you still want to wash it, wash it inside out on a special wool wash program at a maximum of 30 degrees and use a wool detergent, preferably with lanolin and no fabric softener. Do not spin too hard and let it dry lying on a dry towel in the fresh air. Do not use a dryer at all!
Washing by hand in soapy water with wool detergent is always a good idea. This way you will enjoy your woolen clothing for years to come. Order this wool detergent at the same time, then you're always in the right place.