Docs: Enhance initial-setup README prioritising docker and refining PGAdmin steps

Rebased branch onto current `main` ; some earlier overlapping edits were already
incorporated upstream. This commit:
- Moves Docker setup to Option A so new developers see the simplest path first.
- Adds a brief note explaining what the `.env` file stores.
- Expands PGAdmin instructions with step-by-step UI guidance.

Author: astro-ing

bootcamp/materials/1-dimensional-data-modeling/README.md

@@ -40,27 +40,7 @@ cd data-engineer-handbook/bootcamp/materials/1-dimensional-data-modeling
 
 ### Step 2️⃣: Start PostgreSQL
 
-#### 🧩 Option A: Local Installation (Manual Setup)
-
-1. Install PostgreSQL  
-   - [Mac – use Homebrew](https://brew.sh/)  
-   - [Windows – official installer](https://www.postgresql.org/download/)
-
-2. Restore the sample database:
-
-```bash
-pg_restore -c --if-exists -U <your-username> -d postgres data.dump
-```
-
-If that fails, try:
-
-```bash
-pg_restore -U [username] -d [db_name] -h [host] -p [port] data.dump
-```
-
----
-
-#### 🐳 Option B: Docker (Simplest & Preferred)
+#### 🐳 Option A: Docker (Simplest & Preferred)
 
 1. Install [Docker Desktop](https://www.docker.com/products/docker-desktop)  
 2. Copy the env template:
@@ -69,6 +49,8 @@ pg_restore -U [username] -d [db_name] -h [host] -p [port] data.dump
 cp example.env .env
 ```
 
+> The `.env` file stores credentials used by PostgreSQL and PGAdmin
+
 3. Start PostgreSQL & PGAdmin in containers:
 
 ```bash
@@ -93,6 +75,26 @@ docker compose stop
 
 ---
 
+#### 🧩 Option B: Local Installation (Manual Setup)
+
+1. Install PostgreSQL  
+   - [Mac – use Homebrew](https://brew.sh/)  
+   - [Windows – official installer](https://www.postgresql.org/download/)
+
+2. Restore the sample database:
+
+```bash
+pg_restore -c --if-exists -U <your-username> -d postgres data.dump
+```
+
+If that fails, try:
+
+```bash
+pg_restore -U [username] -d [db_name] -h [host] -p [port] data.dump
+```
+
+---
+
 ### Step 3️⃣: Connect to PostgreSQL
 
 Choose any GUI tool you like. Here’s how:
@@ -102,14 +104,20 @@ Choose any GUI tool you like. Here’s how:
 1. Go to [http://localhost:5050](http://localhost:5050)  
 2. Log in using the credentials from your `.env` file  
 3. Create a new server:  
-   - **Name**: Name of your choice  
-   - **Host**: `my-postgres-container`  
-   - **Port**: `5432`  
-   - **Database**: `postgres`  
-   - **Username**: `postgres`  
-   - **Password**: `postgres`  
-   - ✅ Save Password  
+	1. `Dashboard` ➜ `Quick Links` ➜ `Add New Server`
+	2. Under the `General` tab: give it a friendly `Name`, e.g. `Data-Engineer-Handbook-DB`
+	3. `Connection` tab: Copy in credentials from `.env`, where the defaults are:
+	   - **Name**: Name of your choice  
+	   - **Host**: `my-postgres-container`  
+	   - **Port**: `5432`  
+	   - **Database**: `postgres`  
+	   - **Username**: `postgres`  
+	   - **Password**: `postgres`  
+	   - ✅ Save Password  
 4. Click **Save** — and you’re connected!
+5. Expand `Servers`  › *`your-server`* › `Databases` › `postgres`
+	- The database must be highlighted to be able to open the `Query Tool`
+	- Further expanding `postgres` › `Schemas` › `public` › `Tables` should show the expected content
 
 ---