Snowy Thicket encounter
The documented combat move is Stab, an immediate swing after approaching for 3 base damage. There is no documented charged phase or summon wave to build around. Practice that arrival timing and spend your actions dealing damage or restoring only what you need.
Finding the card vendor later
In Telamon’s Manor, Banished Knight sells cards. The listed stock includes Power Shot at 200 TIX, Charge DEF at 50 TIX and Deep Focus at 35 TIX. Use the displayed shop stock for your current save; defeating a fictional second phase is not the unlock step.