diff --git a/GB_set_key_state.md b/GB_set_key_state.md
index 681c2ab..04f0ce6 100644
--- a/GB_set_key_state.md
+++ b/GB_set_key_state.md
@@ -6,8 +6,14 @@ In `joypad.h`
 
 ## Description
 
-TBD
+Sets the state for button `index` to value `pressed` (`true` means down, `false` means released).
 
 ## Thread Safety
 
 `GB_set_key_state` is thread-safe and can be called from any thread and context.
+
+## See Also
+
+* [[GB_key_t]]
+* [[GB_set_key_state_for_player]]
+* [[GB_set_key_mask]]