add information to readme

Author: Calsign

README.md

@@ -1,2 +1,33 @@
 
 [OpenCV](http://opencv.org/) bindings for [OCaml](http://ocaml.org/).
+
+## Quick start
+
+Run `make` to install the library with ocamlfind. You must have OpenCV
+installed on your system.
+
+Run `make demos/basic` to run the demo. This demo requires you to
+provide a video file `demos/basic/test.mp4` as input. It also requires
+you to install the `owl` opam package.
+
+Run `make docs` to generate documentation. Open
+`opencv.docdir/index.html` to view.
+
+## Goals
+
+ - Provide access to the full OpenCV API through OCaml
+ - Make it possible to use OpenCV API calls as pure functions
+ - Use auto-generation of bindings as much as possible
+
+## Caveats
+
+The bindings are currently for a small subset of the OpenCV API (core,
+imgproc, videoio, and highgui), but the plan is to eventually support
+the entire API.
+
+Tested with OpenCV 4.3.0. Should work fine with any OpenCV 4.x, but
+modifications may be necessary to work with older versions.
+
+OWL is not required to use the OpenCV bindings, but it is recommended
+because the mat type is compatible with OWL type
+`Dense.Ndarray.Generic`; OWL serves a role similar to numpy for Python.