docs: README and install instructions

Author: AndyTWF

README.md

@@ -4,15 +4,72 @@ A Software Development Kit (SDK) for the ECFMP Flow Control API
 
 ## Integrating With The SDK
 
-Coming soon!
+### Create a HTTP Client
 
-## Building
+Rather than ship with an opinionated viewpoint as to what you should use for HTTP requests, this SDK
+provides an interface `HttpClient` that the HTTP client of your choice must implement.
+
+### Create a logger
+
+You can optionally pass the SDK a logging class that implements the `Logger` interface. This will allow you to log
+messages from the SDK.
+
+### Create an instance of the SDK
+
+To create an instance of the SDK, you must use the `SDKFactory` class. This class will allow you to configure the SDK,
+and
+then create an instance of it.
+
+```c++
+#include "ECFMP/SDKFactory.h"
+#include "ECFMP/SDK.h"
+
+auto http = std::make_shared<MyHttpClient>();
+auto logger = std::make_shared<MyLogger>();
+auto ecfmp = ECFMP::Plugin::SdkFactory::Build()
+        .WithLogger(logger)
+        .WithHttpClient(std::move(http)).Instance();
+```
+
+### Add the SDK to EuroScopes timer event
+
+The SDK needs to be called periodically to process events. To do this, you must add the call to the EuroScopes timer
+event. This is necessary because EuroScope requires that calls to its internal classes are made from the plugin thread
+(as opposed to something asynchronous.)
+
+```c++
+void MyPlugin::OnTimer(int time)
+{
+    ecfmp.OnEuroscopeTimerTick();
+}
+```
+
+### Register event handlers
+
+You can register event handlers with the SDK. These event handlers will be called when the SDK processes an event.
+These listeners must implement the `EventListener` interface.
+
+```c++
+auto eventListener = std::make_shared<MyListener<ECFMP::Plugin::FlowMeasureActivatedEvent>>();
+ecfmp.EventBus().Subscribe<ECFMP::Plugin::FlowMeasureActivatedEvent>(eventListener);
+```
+
+## Known Limitations
+
+At the moment, the SDK has the following limitations:
+
+- The SDK does not support Event Participation filters on Flow Measures. This is because EuroScope does not provide
+  the CID of the aircraft that is being filtered on, and thus a way around this needs to be devised.
+
+## Development
+
+### Building
 
 This project builds using CMake. You can build using a command similar to below
 
 `cmake -DCMAKE_BUILD_TYPE=<Release|Debug> -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DCMAKE_DEPENDS_USE_COMPILER=FALSE -G Ninja -Bbuild`
 
-## Running Tests
+### Running Tests
 
 Tests can be run using the `ctest` command, from the build directory:
 
@@ -24,8 +81,13 @@ The SDK has the following design rationale.
 
 ### Event Driven
 
-Similar to how EuroScope is event driven, so is this SDK. Integrations can register a series of event handlers with the SDK, which will pass on events, such as new Flow Measures for processing.
+Similar to how EuroScope is event driven, so is this SDK. Integrations can register a series of event handlers with the
+SDK, which will pass on events, such as new Flow Measures for processing.
+
+The SDK itself is also event driven, and uses an internal event bus to handle events.
 
 ### Async
 
-EuroScope is a single-threaded application when it comes to plugins, therefore, anything that may take a while (e.g. HTTP requests) will be done aysynchronously. The results of these operations will be deferred for when the EuroScope thread comes back around, as EuroScope sometimes doesn't like things interacting with it asynchronously.
+EuroScope is a single-threaded application when it comes to plugins, therefore, anything that may take a while (e.g.
+HTTP requests) will be done asynchronously. The results of these operations will be deferred for when the EuroScope
+thread comes back around, as EuroScope sometimes doesn't like things interacting with it asynchronously.