Added usage to readme (fix #1)

README.md

@@ -4,4 +4,27 @@ Native VSCode debugger. Currently only using GDB.
 
 ![https://i.imgur.com/ANEvaZg.png](https://i.imgur.com/ANEvaZg.png)
 
+## Usage
+
+Open your project and click the debug button in your sidebar. At the top right press
+the little gear icon and select GDB. It will automatically generate the configuration
+you need. Now you need to change target to the application you want to debug relative
+to the cwd. (Which is the workspace root by default)
+
+Now you need to first build your application and run it using the green start button
+in the debug sidebar. Multithreading and removing breakpoints while running does not
+work at the time of writing. Also stopping the program sometimes does not work properly.
+
+Extending variables is very limited as it does not support child values of variables.
+Watching expressions works partially but the result does not get properly parsed and
+it shows the raw GDB output of the command. It will run `data-evaluate-expression`
+to check for variables.
+
+While running you will get a console where you can manually type GDB commands or GDB/MI
+commands prepended with a hyphen `-`. The console shows all output GDB gives separated
+in `stdout` for the application, `stderr` for errors and `log` for GDB log messages.
+
+Some exceptions/signals like segmentation faults will be catched and displayed but
+it does not support for example most D exceptions.
+
 ## [Issues](https://github.com/WebFreak001/code-debug)