docs: added troubleshooting guide for cma (medusajs#3756)

docs/content/create-medusa-app.mdx

@@ -139,6 +139,12 @@ Please note that the `yarn dev` command is shown by default for storefronts and
 
 ---
 
+## Troubleshooting
+
+If you run into any errors during the installation, please refer to [this troubleshooting guide](./troubleshooting/create-medusa-app-errors.md) for a potential help.
+
+---
+
 ## Project Directory Structure
 
 Inside the root project directory which was specified at the beginning of the installation process you’ll find the following directory structure:

docs/content/troubleshooting/create-medusa-app-errors.md

@@ -0,0 +1,16 @@
+# Common Create-React-App Errors
+
+## TypeError: cmd is not a function
+
+This error typically occurs when you set up a Medusa project with `create-medusa-app` and try to run the Medusa backend.
+
+To resolve this issue, make sure you change into the `backend` directory of the Medusa project you created before trying to start the Medusa backend:
+
+```bash npm2yarn
+cd backend
+npm run start
+```
+
+## Other Errors
+
+If you ran into another error, please try to search through [our GitHub issues](https://github.com/medusajs/medusa/issues) to see if there's a solution for your issue. If not, please [create an issue on GitHub](https://github.com/medusajs/medusa/issues/new?assignees=olivermrbl&labels=status:+needs+triaging,+type:+bug&template=bug_report.md&title=) and our team will help you resolve it soon.

www/docs/sidebars.js

@@ -293,6 +293,11 @@ module.exports = {
           type: "category",
           label: "Installation Errors",
           items: [
+            {
+              type: "doc",
+              id: "troubleshooting/create-medusa-app-errors",
+              label: "Create Medusa App Errors",
+            },
             {
               type: "doc",
               id: "troubleshooting/cli-installation-errors",