improved installation instructions (#1113)

Author: RemDelaporteMathurin

docs/source/installation.rst

@@ -3,9 +3,7 @@ Installation
 ============
 
 
-FEniCSx can be installed with Anaconda on MacOs and Linux. 
-In order to use the Anaconda distribution on Windows, 
-use the `Windows Subsystem for Linux <https://learn.microsoft.com/en-us/windows/wsl/install>`_. 
+Because the main dependency FEniCSx (dolfinx) cannot be installed natively on Windows, Windows users must use the `Windows Subsystem for Linux <https://learn.microsoft.com/en-us/windows/wsl/install>`_ (WSL). FEniCSx can be installed natively on MacOs and Linux.
 
 .. tip::
     You can install `WSL <https://learn.microsoft.com/en-us/windows/wsl/install>`_ by running
@@ -16,6 +14,12 @@ use the `Windows Subsystem for Linux <https://learn.microsoft.com/en-us/windows/
     use with Windows due to the 
     `WSL extension <https://marketplace.visualstudio.com/items?itemName=ms-vscode-remote.remote-wsl>`_.
 
+
+Option 1: Conda (Recommended)
+-----------------------------
+
+The easiest way to install FESTIM with all its dependencies (including dolfinx) is via Conda.
+
 First `install Anaconda <https://docs.continuum.io/anaconda/install>`_,
 
 .. tip::
@@ -28,8 +32,43 @@ First `install Anaconda <https://docs.continuum.io/anaconda/install>`_,
     You can install other versions by replacing :code:`Anaconda3-2024.06-1-Linux-x86_64.sh` 
     with another from `the official repository <https://repo.anaconda.com/archive/>`_.
 
-then run the following commands::
+Then run the following commands to create an environment and install FESTIM::
 
     conda create -n festim-env
     conda activate festim-env       
-    conda install -c conda-forge festim>=2.0a0
+    conda install -c conda-forge festim
+
+**Specific versions**
+
+To install a specific version of FESTIM, you can specify it in the installation command::
+
+    conda install -c conda-forge festim=0.9.0
+
+To check which version of FESTIM is currently installed, run::
+
+    conda list festim
+
+**Nightly / development version**
+
+We provide a nightly conda build via our own anaconda channel. You can install it with::
+
+    # Nightly / development version
+    conda install -c festim-dev/label/nightly -c conda-forge festim
+
+    # Or with a pin to latest nightly
+    conda install -c festim-dev/label/nightly -c conda-forge festim=*=nightly_*
+
+
+Option 2: Docker
+----------------
+
+Installing the FEniCSx docker container and then installing FESTIM with pip inside it is also an option::
+
+    docker run -ti dolfinx/dolfinx:stable
+    pip install festim
+
+
+Option 3: From Source
+---------------------
+
+When none of the above methods are possible, users can build FEniCSx from source and then install FESTIM and all dependencies manually. Please refer to the `FEniCSx documentation <https://docs.fenicsproject.org/>`_ for complete instructions on building dolfinx from source.