wip: Add basic usage docs to README.md.

README.md

@@ -2,6 +2,41 @@
 
 Provides features for crop planning in [farmOS](https://farmOS.org).
 
+## Usage
+
+1. Install the module.
+2. Create a new Crop plan.
+    1. Go to Plans > Crop in the main menu, then click "Add Crop Plan".
+    2. Give the plan a name (eg: "2024 Beans").
+    3. Optionally add additional metadata (Season, Notes, Flags, etc).
+    4. Click "Save".
+3. Populate the plan with crop plantings.
+    - Manually:
+        - Create new Plant assets:
+            1. ...
+        - Add existing Plant assets:
+            1. ... 
+    - CSV import:
+        1. ...
+4. View/update the plan during the season.
+   1. Go to Plans > Crop in the main menu.
+   2. Click on the name of the crop plan.
+   3. Visualize the planting timeline.
+       - ...
+   4. Update planting details.
+       - Manually:
+           1. ...
+       - CSV import:
+           1. ... 
+5. Archive the plan at the end of the season.
+    1. Go to Plans > Crop in the main menu.
+    2. Click the checkbox next to the plan.
+    3. Select "Archive plan" from the "Action" dropdown, and click "Apply to
+       selected items".
+
+Archived plans can be viewed using the "Filter" options at the top of the list
+of plans.
+
 ## Maintainers
 
 Current maintainers: