make explanations more complete

Setup/README.md

@@ -14,6 +14,12 @@ to distribution. On Archlinux you can run
 
 Check the name of the package for your distribution and the documentation of your
 package manager to see how to install docker in your case.
+Adding yourself to the docker group can by done by running
+
+    sudo gpasswd -a <username> docker
+
+where <username> is to be replaced by your user name.
+
 On `systemd`-based systems the daemon is started by running
 
     sudo systemctl start docker
@@ -60,10 +66,13 @@ If you have trouble with internet connection inside the container use
 
 
 ## Start LDD-TPR container and step into the container
+From anywhere in the command line you can start the docker container by running
 
     docker start LDD-TPR & docker exec -ti -u fenics LDD-TPR /bin/bash -l
 
-you should see a message like the following
+Tip: This command should be stored as a script or alias to not have to remember it.
+
+You should see a welcome message greeting you
 ```
 # FEniCS stable version image
 
@@ -79,13 +88,28 @@ example:
     cd ~/demo/python/documented/poisson
     python3 demo_poisson.py
 ```
-Tip: This command should be stored as a script or alias to not have to remember it.
-You should see a welcome message greeting you
+
 
 It is good practice to update the system in your `docker image` so run
 
     sudo apt-get update && sudo apt-get upgrade
-    
+
+## Install missing python3 modules
+Once you are in the container navigate into the `Setup` of the cloned repository.
+This should be achieved by running
+
+    cd shared/setup
+
+within the container. Then run
+
+    pip3 install -r python_requirements.txt
+
+to install missing python requirements needed to run `LDDsimulation` based
+code.
+
+Concrats, now you can test the installation by running an example in the
+[Usecases](../Usecases) folder of the `LDDsimulation` repo.
+
 ## Usefull docker commands
 
 List all docker container
@@ -132,7 +156,7 @@ check your dns settings.
 ## Nützliche FEniCS Links
 
 
-- Forum, viele Fragen wurden evtl. schon gestellt, bzw. können ggf. gestellt werden:
+- Fenics based forums:
 
     https://www.allanswered.com/community/s/fenics-project/