Add deployment instructions for Netlify in README

browser/create-template/templates/nextjs-site/README/DEPLOYING.md

@@ -1,3 +1,15 @@
 # Deploying
 
 ## Deploying to Netlify
+
+### Prerequisites
+
+- A [Netlify](https://www.netlify.com/) account
+- A Git repository with your template project
+
+### Steps
+
+1. Click on the "Add new site" button and select "Import an existing project".
+2. Choose your Git provider and select the repository where your project is located.
+3. Add the environment variables required by your project
+4. Click on the "Deploy site" button.