feat: add clearer instructions on install. (#1309)

Author: tnolet

site/static/docs/ai/checkly.rules.md

@@ -1,7 +1,6 @@
 # Checkly
 
 - Refer to docs for Checkly CLI v6.0.0 and above.
-- To generate the initial setup for Checkly use the command `npm create checkly@latest`
 - Check the Checkly CLI output to figure out into which folder the setup was generated
 - Use the [Checkly CLI reference documentation](https://www.checklyhq.com/docs/cli/command-line-reference)
 - Use the [Checkly construct reference documentation](https://www.checklyhq.com/docs/cli/constructs-reference)
@@ -14,6 +13,11 @@
 - If endpoints require authentication ask the user which authentication method to use and then generate a setupScript to authenticate the given requests
 - Referenced setupScript for ApiChecks must be plain ts files and not export anything
 
+## Installing the Checkly CLI
+
+- Always use `npm create checkly@latest`.
+- Do not make up commands that do not exist.
+
 ## Project Structure
 
 - `checkly.config.ts` - Mandatory global project and CLI configuration. We recommend using TypeScript.