Install fixes.

README.md

@@ -56,7 +56,7 @@ sudo apt install openssh-server
 
 Follow the steps below to setup the software required to execute
 Jupyter Notebooks on your native comupter or in a virtual machine.
-You must have the aministrator/root priviliges on the machine.
+You must have the aministrator/root privileges on the machine and basic/intermediate knowledge of Linux.
 
 ### Ubuntu 18.04
 
@@ -106,9 +106,7 @@ does not require a password. If it does you should fix the required permissions.
 ```bash
 sudo visudo
 ```
-
-(use "sudo visudo" to edit permissions,
-add NOPASSWD: in the right place). That is edit the line:
+and add ```NOPASSWD:```  by changing the line:
 ```bash
 %sudo   ALL=(ALL:ALL) ALL
 ```
@@ -117,13 +115,13 @@ to
 %sudo  ALL=(ALL:ALL) NOPASSWD: ALL
 ```
 
-If this is considered a security risk the alternativ is to give the
+If this is considered a security risk the alternative is to give the
 password as argument to the ansible-playbook command:
 ```bash
 ansible-playbook -i hosts playbooks/wara.yml -e ansible_sudo_pass=******
 ```
 
-Install playbooks repo:
+Install the playbooks repo:
 ```bash
 sudo apt install git
 git clone https://gitlab.liu.se/lrs/lrs_playbooks.git
@@ -132,14 +130,14 @@ git clone https://gitlab.liu.se/lrs/lrs_playbooks.git
 In the command below the value of the environment variable specifying
 the login name is used. You don't have to replace it.
 
-Run playbook to install and update the wara developer programs:
+Run playbook to install and update the wara developer programs. It can take several minutes to complete.
 ```bash
 cd lrs_playbooks
 git pull
 ansible-playbook -i hosts playbooks/wara_develop.yml -e user=${USER} -e install_user=${USER}
 ```
 
-Add to .bashrc:
+Add the following commands at the end of ```~/.bashrc``` file:
 ```bash
 export WORLD_ORIGIN_LAT=57.7605573519 
 export WORLD_ORIGIN_LON=16.6827607783
@@ -149,15 +147,18 @@ export WORLD_ORIGIN_ELEVATION=29.8
 source ${HOME}/wara_ws/devel/setup.bash
 export PATH=${HOME}/waraps/script:${PATH}
 ```
+These commands will take effect next time you open a new terminal window or login to the system.
+
+At this point your system now has the necessary software installed.
 
-Test 3D graphics
+You can use the following commands to test the 3D graphics hardware and driver setup on your system:
 
 ```bash
 glxgears
 glmark2
 ```
 
-Test Gazebo
+If the above commands execute without errors you can test that Gazebo works correctly on your system:
 
 ```bash
 roslaunch lrs_wara_gazebo gazebo.launch