Difficulty understanding Server-Side Rendering (SSR)

**Issue:**
I'm having trouble grasping the concept of Server-Side Rendering (SSR) in Next.js. I've gone through the documentation, but I'm still unclear on how it works and when to use it.

**Steps to Reproduce:**
1. ...
2. ...

**Expected Behavior:**
I expect to have a clear understanding of SSR and its practical use cases.

**Additional Information:**
- Next.js version: X.X.X
- Relevant code snippets: [insert code here]

The issue does not identify a repository file, test, or entry point. Start by reviewing the existing SSR documentation and determine which explanation of how SSR works and when to use it is missing. Done means the documentation clearly explains SSR and its practical use cases.

Written by the indexing model from the issue text.