Improve instructions in readme

README.md

@@ -31,6 +31,8 @@ witness is a binary buffer with all the signals in binnary format.  The buffer i
 
 You can use the tool to build the binary file from the witness.json file generated by [snarkjs](https://github.com/iden3/snarkjs).
 
+### IMPORTANT: Please be sure you run your setup with `--protocol groth`  websnark only generates groth16 proofs!
+
 ```
 node ../tools/buildwitness.js -i witness.json -o witness.bin
 ```
@@ -102,6 +104,22 @@ function calcProof() {
 </html>
 ```
 
+You can test it by running a web server on the example directory
+
+```
+npm -g install http-server
+cd example
+http-server .
+```
+
+And then navegate to [http://127.0.0.1:8080](http://127.0.0.1:8080)
+
+The generated proof can be cut and pasted to `example/proof` and tested with snarkjs
+
+```
+snarkjs verify
+``
+
 ## Building wasm.js
 
 ```