Hi, I am an avid gardener, but just started growing clematis. This is a Silver Moon clematis I planted last summer that seems to be struggling this year. Likely some slugs got to it a few weeks ago. Last year it had two shoots, this year one. Any advice on how to revive it? Unsure if or where I should prune it to produce more shoots.

Sometimes it just takes tome for the roots to put down good growth before they start increasing their branching.
If it was mine, I would pull away the bark, it's a perfect hiding and breeding area for slugs, snails and earwigs, all that love to damage the leaves and blooms. Add a layer of good compost instead, with regular watering, it feeds the roots and I always notice new good growth when I add that compost.