Add and extend section from fmu-sumo readme

README.md

@@ -1,2 +1,54 @@
 # fmu-sumo-uploader
-Uploads results to azure using sumo
+Upload data from FMU to Sumo
+
+### Concepts
+`SumoConnection`: The SumoConnection object represents the connection to Sumo, and will handle authentication etc when initiated. This object uses the Sumo python wrapper under the hood.
+
+`CaseOnDisk`: The CaseOnDisk object represents an ensemble of reservoir model realisations. The object relates to the case metadata. Individual files belonging to the case are represented as FileOnDisk objects.
+
+`FileOnDisk`: The FileOnDisk object represents a single file in an FMU case, stored on the local disk.
+
+`CaseOnJob`: Similar to CaseOnDisk, but does not refer to files on disk. Instead uses in-memory structures.
+
+`FileOnJob`: Similar to FileOnDisk, but uses in-memory structures.
+
+### workflow for uploading during ERT runs
+
+HOOK (presim) workflow registering the case:
+```python
+from fmu.sumo import uploader
+
+# Establish connection to Sumo
+connection = sumo.SumoConnection()
+
+# Initiate the case object
+case = sumo.CaseOnDisk(
+    case_metadata_path="/path/to/case_metadata.yml",
+    sumo_connection=sumo_connection
+    )
+
+# Register the case on Sumo
+# This uploads case metadata to Sumo
+case.register()
+```
+
+FORWARD_JOB uploading data (can be repeated multiple times during a workflow):
+```python
+from fmu.sumo import uploader
+
+# Establish connection to Sumo
+connection = sumo.SumoConnection()
+
+# Initiate the case object
+case = sumo.CaseOnDisk(
+    case_metadata_path="/path/to/case_metadata",
+    sumo_connection=sumo_connection
+    )
+
+# Add file-objects to the case
+case.add_files("/globable/path/to/files/*.gri")
+
+# Upload case data objects (files)
+case.upload()
+
+```