The Road of Kings will have a sizable section on Brythunia.
If you cannot wait that long, here are some stories that take place (at least in part) in Brythunia that you can read for inspiration:
Conan the Savage (Leonard Carpenter)
Conan the Hunter (Sean A. Moore)
Conan and the Amazon (John Maddox Roberts)
Savage Sword of Conan #8, "Sorcerer's Summit" (Bruce Jones)
Conan the Barbarian, Vol. 1, No. 3, 'The Twilight of the Grim Grey God' (Roy Thomas)
Conan the Barbarian, Vol. 1, No. 157, 'The Wizard'. (Michael Fleisher)
Conan the Adventurer #3, "Blood Days in Brythunia" (Roy Thomas)
Conan the Adventurer #5, "The Woman Who Walks Alone" (Roy Thomas)