Add more details to README

Author: k4rtik

README.md

@@ -1,3 +1,30 @@
 # OpenQASM Parser
 
-- OCaml library for manipulating OpenQASM Abstract Syntax Tree
+OCaml library for manipulating [OpenQASM](https://github.com/Qiskit/openqasm) Abstract Syntax Tree
+
+## Requirements
+This library requires a recent version of OCaml, `dune` and `menhir`.
+
+## Installation
+
+Use the package manager [opam](https://opam.ocaml.org/) to install OpenQASM parser.
+
+```bash
+opam install openQASM
+```
+
+Or use the standard `make build` and `make install` commands.
+
+## Usage
+
+To play with the library, run `dune utop` and issue a command such as:
+
+```ocaml
+OpenQASM.get_ast "teleport.qasm";;
+```
+
+## Contributing
+Pull requests are welcome.
+
+## License
+[MIT](https://choosealicense.com/licenses/mit/)