First things first, make sure you've got Node.js and npm on your computer. Then, you can install the Firebase CLI using npm:

npm install -g firebase-tools

Log in to Firebase with the CLI:

firebase login

Next, go to your project directory and initialize Firebase:

firebase init

During the setup, choose:

• Hosting: Set up files for Firebase Hosting.
• Use an existing project: If you already have a Firebase project, pick it.

When asked, give the public directory (usually build or dist) and set it up as a single-page app by saying Yes to redirects.

Make sure your single-page app is built and ready to go. For example, with React, you might run:

npm run build

Ensure the build output directory matches the public directory you specified during Firebase initialization (like build).

Firebase will create a firebase.json file. A typical setup might look like this:

{
  "hosting": {
    "public": "build",
    "ignore": [
      "firebase.json",
      "**/.*",
      "**/node_modules/**"
    ],
    "rewrites": [
      {
        "source": "**",
        "destination": "/index.html"
      }
    ]
  }
}

The rewrites array makes sure all routes go to index.html, which is crucial for SPAs.

Deploy your app:

firebase deploy

This will upload your built SPA to Firebase Hosting and give you a public URL for your app.

After deploying, Firebase will give you a link to your hosted app. Visit the URL to make sure everything works as expected. If there are issues, check the build and firebase.json configuration. Tweak as needed.