howdy and welcome to WMT.
Swenson grapes get pruned like all others, that means that fruit forms on one year old wood. The picture suggests a three year old vine/ lots of young growth. This year I start picking two healthy leaders and remove side shoots. I would protect it from rabbit damage over winter with fence (good). In spring before buds pop I choose one or two healthy stems to develop the plant around. Everything else is trimmed off. The two healthy stems are trained on a post and at the end on next summer hopefully there are two healthy arms on the trellis system.
Good luck! I really like Briana and use it as a fill in for empty spots, ,,, Edelweiss as a young plant would drop grapes at 15 brix, today they hang better and can get to 18 brix.