additional package installation info

appendix-A/01_optional-python-setup-preferences/README.md

@@ -28,6 +28,8 @@ where `Desktop/` is the folder where the Miniforge installer was downloaded to.
 
 Next, step through the download instructions, confirming with "Enter".
 
+
+
 ## 2. Create a new virtual environment
 
 After the installation was successfully completed, I recommend creating a new virtual environment called `dl-fundamentals`, which you can do by executing
@@ -38,6 +40,8 @@ conda create -n LLMs python=3.10
 
 <img src="figures/new-env.png" alt="new-env" style="zoom:33%;" />
 
+> Many scientific computing libraries do not immediately support the newest version of Python. Therefore, when installing PyTorch, it's advisable to use a version of Python that is one or two releases older. For instance, if the latest version of Python is 3.13, using Python 3.10 or 3.11 is recommended.
+
 Next, activate your new virtual environment (you have to do it every time you open a new terminal window or tab):
 
 ```bash
@@ -52,7 +56,7 @@ If you want to style your terminal similar to mine so that you can see which vir
 
 
 
-# 3. Install new Python libraries
+## 3. Install new Python libraries
 
 
 
@@ -70,6 +74,24 @@ You can also still use `pip` to install libraries. By default, `pip` should be l
 
 <img src="figures/check-pip.png" alt="check-pip" style="zoom:33%;" />
 
+
+
+## 4. Install PyTorch
+
+PyTorch can be installed just like any other Python library or package using pip. For example:
+
+```bash
+pip install torch==2.0.1
+```
+
+However, since PyTorch is a comprehensive library featuring CPU- and GPU-compatible codes, the installation may require additional settings and explanation (see the *A.1.3 Installing PyTorch in the book for more information*).
+
+It's also highly recommended to consult the installation guide menu on the official PyTorch website at [https://pytorch.org](https://pytorch.org).
+
+<img src="figures/pytorch-installer.jpg" width="600px">
+
+
+
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