You can freely switch between the two in combat, default hotkey Tilde (Left of number 1 key).

How to set up primary and secondary weapons:

  1. Press C to see your equipped items.
  2. Remove any weapons.
  3. Equip primary weapon (for ex sword and shield)
  4. Press the switch key (Default tilde, left of number 1 key)
  5. Equip secondary weapon (for ex lute)