update README

Author: remk

README.md

@@ -9,18 +9,40 @@ This a plugin for LSC, using Microsoft Graph API
 The object of this plugin is to synchronize users from a Microsoft Azure active directory to a referential.
 For example it can be used to synchronize the users in an Azure AD to an LDAP repository.
 
-### Architecture
+### Configuration
 
-WIP
+The plugin connects to Microsoft Graph API as a [deamon app](https://docs.microsoft.com/en-us/azure/active-directory/develop/scenario-daemon-overview). More information on how to register it on Microsoft Azure can
+be found [here](https://docs.microsoft.com/en-us/azure/active-directory/develop/scenario-daemon-app-registration).
 
-### Configuration
+The application must have the `Application permission` `User.Read.All` permission granted. The documentation about permissions and consent can be found [here](https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-permissions-and-consent).
 
-WIP
+At the time being the plugin only allows to connect to the API using a client secret.
 
 ### Usage
 
-WIP
+There are examples of configuration in the `sample` directory. The `lsc.xml` file describes a synchronization from Microsoft Graph API to an LDAP repository.
+
+The values to configure are:
+
+#### Source service
+
+##### Connection
+
+  - `connections.pluginConnection.msGraphApiConnectionSettings.clientId`: The client id for the application
+  - `connections.pluginConnection.msGraphApiConnectionSettings.clientSecret`: The client secret used to connect to the application
+  - `connections.pluginConnection.msGraphApiConnectionSettings.tenant`: The  Azure AD  tenant
+
+##### API parameters
+
+  - `tasks.task.pluginSourceService.filter`: (Optional, default none) The filter to use for fetching the list of pivots. For the syntax to use in those filters the syntax can be found [here](https://docs.microsoft.com/en-us/graph/query-parameters#filter-parameter).
+  - `tasks.task.pluginSourceService.pivot`: (Optional, default `mail`) The field to use as pivot.
+  - `tasks.task.pluginSourceService.pageSize`: (Optional, default none) The page size used to paginate the results from the graph API. Default is no page size, but the API has a `100` default page size.
+  - `tasks.task.pluginSourceService.select`: (Optional, default none) The comma separated list of fields to gather when getting the details of a user. The syntax to use can be found [here](https://docs.microsoft.com/en-us/graph/query-parameters#select-parameter). By default the API returns a default set of properties.
 
+The jar of the Microsoft graph API LSC plugin must be copied in the `lib` directory of your LSC installation. Then you can launch it with the following command line:
+```
+`̀`` JAVA_OPTS="-DLSC.PLUGINS.PACKAGEPATH=org.lsc.plugins.connectors.msgraphapi.generated" bin/lsc --config /path/to/sample/msgraphapi-to-ldap/ --synchronize users --clean users --threads 5
+```
 ### Packaging
 
 WIP