Update ktor.md

Author: martinbonnin

Writerside/topics/ktor.md

@@ -5,6 +5,8 @@
 
 ## Add apollo-execution-ktor to your project
 
+> Make sure to follow the steps in ["Getting started"](getting-started.md) first to generate your `ServiceExecutableSchemaBuilder`.
+
 To use the Ktor integration, add `apollo-execution-ktor` to your dependencies and a Ktor engine:
 
 ```kotlin
@@ -34,6 +36,3 @@ embeddedServer(Netty, port = 8080) {
   apolloSandboxModule()
 }.start(wait = true)
 ```
-
-> `ServiceExecutableSchemaBuilder` is generated by the KSP processor. See ["Getting started"](getting-started.md) for more details.
-