Update instructions for installing necessary modules.

Running-from-source.md

@@ -1,24 +1,22 @@
 Running from source
---------
+===
 
-Download and extract the [latest source code](https://github.com/EDCD/EDMarketConnector/archive/master.zip) (or fork and clone if you're comfortable with using `git`).
+1. Download and extract the [latest source code](https://github.com/EDCD/EDMarketConnector/archive/main.zip) (or fork and clone if you're comfortable with using `git`).
 
-Mac:
+    *NB: Use `main` branch, not `master` branch* (if the latter even still exists).
 
-* Requires Python 3.7 and the Python “keyring”, “pyobjc”, “requests” and “watchdog” modules - install these with `pip3.7 install keyring pyobjc requests watchdog`.
-* Run with `python ./EDMarketConnector.py` .
+1. Ensure you have 'pip' or 'pip3' installed, see [Installing pip](https://packaging.python.org/guides/installing-using-pip-and-virtual-environments/#installing-pip).
 
-Windows:
+1. Ensure additional necessary Python modules are installed with `pip install -r requirements.txt` .
+    * Note that on Debian (at least up to and including 10.x aka 'Buster') you'll `pip3 install -r requirements.txt` .
+    * If you get 'command not found' or similar for the 'pip' command then try: `python -m pip install -r requirements.txt` .
 
-* Requires Python 3.7 and the Python “keyring”, “requests” and “watchdog” modules - install these with `pip3.7 install keyring requests watchdog`
-* Run with `EDMarketConnector.py` .
+1. Run this application:
 
-Linux:
+    * Linux: `./EDMarketConnector.py` .
+    * Mac: `python ./EDMarketConnector.py` .
+    * Windows: `EDMarketConnector.py` .
 
-* Requires Python 3.7 and the Python “requests” and "tkinter" modules.
-  - On Debian-based systems install these with `sudo apt-get install python-iniparse python-requests python-tk` .
-  - On Arch, install these with `sudo pacman -S python2 python2-requests tk; sudo easy_install-2.7 iniparse` .
-* Run with `./EDMarketConnector.py` .
 
 Command-line
 --------