Update README.md

[Meherzi Zied (Zied031)]

I added a short "New User Note" at the top of the README to guide beginners on how to navigate and start using the repository effectively.

[Manya Sharma (ManyaS-Git)]

Good, minimal change — approved.

I verified the note's claims against the current README.md on master and they all check out:

• "Getting Started" section exists below (TOC + # Getting Started <a name="Getting-Started">), so "start by exploring the 'Getting Started' section below" is accurate.
• AI100 - Samples, AI200 - Reference Architectures, and AI300 - Best Practices all exist as sections, so the recommendation to start with AI100 before AI200/AI300 matches the actual structure.

Nice touches:

• It's a > blockquote, so it reads as a callout rather than competing with the existing intro paragraph.
• It doesn't touch any of the existing content or links — no merge conflicts, no regressions.

One optional suggestion (not blocking): instead of referring to the sections by name, you could link them directly, e.g. [**"Getting Started"**](#getting-started) and [**AI100 - Samples**](#ai100), so the note is immediately clickable for newcomers. That would make it fully self-contained navigation.