installation-instructions.md

@@ -95,6 +95,8 @@ where `DISTRIBUTION` can be any one of
 bookworm, bullseye, buster, sid, bionic, focal, jammy, kinetic
 ```
 
+(You should use instead ``arch=arm64`` above if you are using that architecture.)
+
 You should then download the public key [`612DEFB798507F25`](https://keys.openpgp.org/search?q=612DEFB798507F25) to verify the packages, with the command:
 ```
 apt-key adv --keyserver keyserver.ubuntu.com --recv-key 612DEFB798507F25