diff --git a/README.md b/README.md
index 953ea63..2f09231 100644
--- a/README.md
+++ b/README.md
@@ -54,7 +54,7 @@ $ open WireGuard.xcodeproj
      the "External Build Tool Configuration":
      
      ```
-     $BUILD_DIR/../../SourcePackages/checkouts/wireguard-apple/Sources/WireGuardKitGo
+     ${BUILD_DIR%Build/*}SourcePackages/checkouts/wireguard-apple/Sources/WireGuardKitGo
      ```
      
    - Switch to "Build Settings" and find `SDKROOT`.