Updated with clarification information on clusters

README.md

@@ -107,30 +107,30 @@ Boom! PostgreSQL is installed and ready to go! 🎉
 
 PostgreSQL uses **clusters** to manage databases. We’re going to create a new cluster that runs on a different port, so you can keep things organized.
 
-### Step 1: Create a New Cluster
+### Step 1: Create a New Cluster (the Default Cluster named ‘main’ is running on port 5432)
 
 Run the following command to create a cluster on port `5436`:
 
 ```bash
-sudo pg_createcluster 14 main5436 --port=5436
+sudo pg_createcluster 16 main5436 --port=5436
 ```
 
-This will create a new cluster for **PostgreSQL version 14**. Clusters are isolated instances of PostgreSQL.
+This will create a new cluster for **PostgreSQL version 16**. Clusters are isolated instances of PostgreSQL.
 
 ### Step 2: Start the Cluster
 
 Next, start your new cluster:
 
 ```bash
-sudo service postgresql@14-main5436 start
+sudo service postgresql@16-main5436 start
 ```
 
 ### Step 3: Check Cluster Status
 
 Let’s check if everything is running smoothly:
 
 ```bash
-sudo service postgresql@14-main5436 status
+sudo service postgresql@16-main5436 status
 ```
 
 🎉 **Success!** If you see the output saying `Active: active (running)`, your cluster is live and ready to handle databases.
@@ -141,7 +141,9 @@ Switch to the PostgreSQL user and set a password for your main database user:
 
 ```bash
 sudo -i -u postgres
-psql
+
+## run with the -p parameter to connect to the NEW cluster
+psql -p 5436
 ```
 
 Then set the password for the `postgres` user:
@@ -152,6 +154,86 @@ ALTER USER postgres PASSWORD 'yourpassword';
 
 Exit the PostgreSQL prompt by typing `\q`.
 
+### Step 5: Verify that you can login with your `postgres` User:
+
+```bash
+exit  # go back to your default shell, or reopen your terminal
+
+## run with the -p parameter to connect to the NEW cluster
+psql -h localhost -U postgres -p 5436
+
+# it should ask you for the new password and you should be able to login.
+```
+
+Exit the PostgreSQL prompt by typing `\q`.
+
+### Step 5:  🚦 Dealing with the Default Cluster
+By default, when you install PostgreSQL, it creates an auto-start cluster named `main` on port `5432`. This cluster is automatically managed by your system’s init process, meaning it starts when your system boots.
+
+If you’ve created additional clusters (like the one on port `5436`), it’s helpful to know how to manage them:
+
+**Checking Active Clusters**
+To see all the clusters currently configured (and whether they’re running):
+
+```bash
+pg_lsclusters
+```
+You’ll see each cluster’s PostgreSQL version, name, port, and status.
+
+
+1. **Stop the Default Cluster**:
+
+    ```bash
+    sudo pg_ctlcluster 16 main stop
+    ```
+
+2. **Edit the start.conf File**:
+
+    Open the **`start.conf`** file for the default cluster:
+
+    ```bash
+    sudo nano /etc/postgresql/16/main/start.conf
+    ```
+
+    If you see the word **`auto`** in that file, change it to **`manual`**.
+
+3. **Save and Close**: Press **`Ctrl+O`** to save, then **`Ctrl+X`** to exit.
+
+Now, when you start/restart PostgreSQL via **`sudo service postgresql start`**, the **`16/main`** cluster won’t start automatically. To start it manually at any time, just run:
+
+```bash
+sudo pg_ctlcluster 16 main start
+```
+
+
+### Managing Clusters
+
+Use the following commands to manage your clusters:
+
+- **Start a Cluster**:  
+  ```bash
+  sudo pg_ctlcluster <version> <cluster_name> start
+  ```
+
+- **Stop a Cluster**:  
+  ```bash
+  sudo pg_ctlcluster <version> <cluster_name> stop
+  ```
+
+- **Restart a Cluster**:  
+  ```bash
+  sudo pg_ctlcluster <version> <cluster_name> restart
+  ```
+
+- **Reload Configuration** (without restarting):  
+  ```bash
+  sudo pg_ctlcluster <version> <cluster_name> reload
+  ```
+
+Now you have full control over your clusters—start only what you need, stop what you don’t, and keep your environment lean and efficient!
+
+
+
 ---
 
 ## 🌐 **Installing and Configuring pgAdmin (Web Version)**
@@ -199,15 +281,7 @@ During setup, you’ll be prompted to:
 
 The setup script will configure Apache to serve pgAdmin. When prompted to restart Apache, press `y`.
 
-You can now access pgAdmin by navigating to:
-
-```
-http://127.0.0.1/pgadmin4
-```
-or
-```
-http://localhost/pgadmin4
-```
+You can now access pgAdmin by navigating to  http://127.0.0.1/pgadmin4   or   http://localhost/pgadmin4
 
 🎉 You’re now able to manage your PostgreSQL databases using pgAdmin, right from your browser! 🚀