There are plenty of options here. The outfit could be made of woven material or felt (back when good quality wool felt was still available.)
The decorations could be appliqued or embroidered, and the embroidery could be carried out in either knitting worsted or embroidery floss.
Slide fasteners were used for both the jacket and the skirt, using colors that harmonize with the decorations. The jacket is lined, and consistent with the big-shouldered look of the period, pattern pieces are provided for shoulder pads.
View B shows how to put together a very sporty ensemble by making up the jacket on its own and wearing it with a hat and skirt made up in a tweed that harmonizes with the jacket.
I can't quite make out the inscription in blue ink found on the front of the envelope.
The skirt pieces as well as the transfers are missing. I can imagine a young skater's mother making up a whole wardrobe of skating skirts in different colors, to be worn with a variety of jackets and sweaters.
Here's some lovely 1940's home movie footage of skaters.